Total liabilities and stockholders' equity Accumulated other comprehensive income Retained earnings Common stock, $0.01 par value; Authorized: 600,000 shares; Issued and outstanding: 361,382 shares as of August 31, 2009 and 360,976 shares as of May 31, 2009, respectively STOCKHOLDERS' EQUITY Total liabilities Other Liabilities, Noncurrent, Total Deferred Tax Liabilities, Noncurrent Total current liabilities Client fund obligations Client fund obligations Client fund obligations Current liabilities before client fund obligations Current liabilities before client fund obligations Current liabilities before client fund obligations. Other Liabilities, Current, Total Deferred Tax Liabilities, Current Deferred revenue LIABILITIES Total assets Other Assets, Noncurrent, Total Deferred Tax Assets, Net, Noncurrent Goodwill Intangible assets, net of accumulated amortization Property and equipment, net of accumulated depreciation Client fund obligations Current liabilities before client fund obligations Total current assets Deferred Tax Assets, Net, Current Prepaid income taxes Accounts receivable, net of allowance for doubtful accounts Cash and cash equivalents Common stock, par value Common stock, shares authorized Common stock, shares issued Common stock, shares outstanding Cash dividends per common share Weighted-average common shares outstanding, assuming dilution Weighted-average common shares outstanding Diluted earnings per share Basic earnings per share Net income Income taxes Income before income taxes Operating income Total expenses Selling, general and administrative expenses Operating expenses Expenses: Total revenue Interest on funds held for clients Interest on funds held for clients Interest on funds held for clients. Service revenue Revenue: Cash and cash equivalents, end of period Cash and cash equivalents, beginning of period Increase in cash and cash equivalents Net cash used in financing activities Net change in client fund obligations Net change in client fund obligations Net change in client fund obligations. FINANCING ACTIVITIES Net cash (used in)/provided by investing activities Purchases of property and equipment Net change in funds held for clients' money market securities and other cash equivalents Net change in funds held for clients' money market securities and other cash equivalents Net change in funds held for clients' money market securities and other cash equivalents. Proceeds from sales and maturities of available-for-sale securities Purchases of available-for-sale securities INVESTING ACTIVITIES Net cash provided by operating activities Increase (Decrease) In Other Operating Capital, Net Accounts receivable Interest receivable Changes in operating assets and liabilities: Benefit for deferred income taxes Stock-based compensation costs Depreciation and amortization on property and equipment and intangible assets Net income OPERATING ACTIVITIES ASSETS Description of Business and Significant Accounting Policies Description of Business and Significant Accounting Policies [Abstract] Description of Business and Significant Accounting Policies. Funds Held for Clients and Corporate Investments Funds Held for Clients and Corporate Investments [Abstract] Funds Held for Clients and Corporate Investments. Goodwill and Intangible Assets, Net of Accumulated Amortization Goodwill and Intangible Assets, Net of Accumulated Amortization [Abstract] Goodwill and Intangible Assets, Net of Accumulated Amortization. Commitments and Contingencies Commitments and Contingencies [Abstract] Commitments and Contingencies. Funds Held for Clients and Corporate Investments Funds Held For Clients And Corporate Investments Text Block Funds Held for Clients and Corporate Investments. Property and Equipment, Net of Accumulated Depreciation Goodwill and Intangible Assets, Net of Accumulated Amortization Funds Held for Clients and Corporate Investments Comprehensive Income Commitments and Contingencies Related Party Transactions Provision for allowance for doubtful accounts Purchases of other assets Current assets before funds held for clients Current assets before funds held for clients Current assets before funds held for clients. Interest on funds held for clients Current assets before funds held for clients Net change in funds held for clients' money market securities and other cash equivalents Net change in client fund obligations Description of Business and Significant Accounting Policies [Abstract] Funds Held for Clients and Corporate Investments [Abstract] Goodwill and Intangible Assets, Net of Accumulated Amortization [Abstract] Commitments and Contingencies [Abstract] Funds held for clients Additional paid-in capital Net realized gains on sales of available-for-sale securities Dividends paid Description of Business and Significant Accounting Policies Description of Business and Significant Accounting Policies Text Block Description of Business and Significant Accounting Policies Total stockholders' equity Accrued income taxes Accrued Income Taxes, Current Accrued compensation and related items Employee-related Liabilities, Current, Total Employee-related Liabilities, Current Accounts payable Accounts Payable, Current, Total Accounts Payable, Current Net income Basic and Diluted Earnings Per Share Depreciation and amortization on property and equipment and intangible assets Depreciation, Depletion and Amortization, Nonproduction Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Accounts receivable, net of allowance for doubtful accounts Accounts Receivable, Net, Current Funds held for clients Total current assets Assets, Current Property and equipment, net of accumulated depreciation Property, Plant and Equipment, Net, Beginning Balance Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net Intangible assets, net of accumulated amortization Intangible Assets, Net (Excluding Goodwill) Other long-term assets Other long-term assets Other current liabilities Other current liabilities Total current liabilities Liabilities, Current Other long-term liabilities Other long-term liabilities Total liabilities Liabilities Retained earnings Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit) Total liabilities and stockholders' equity Liabilities and Stockholders' Equity Stock-based compensation costs Share-based Compensation Net realized gains on sales of available-for-sale securities Gain (Loss) on Sale of Investments Net change in other assets and liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Purchases of available-for-sale securities Payments to Acquire Available-for-sale Securities Proceeds from sales and maturities of available-for-sale securities Proceeds from Sale and Maturity of Available-for-sale Securities Purchases of other assets Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities (Decrease)/increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Service revenue Sales Revenue, Services, Net Total revenue Revenues Operating income Operating Income (Loss) Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Basic earnings per share Earnings Per Share, Basic Diluted earnings per share Earnings Per Share, Diluted Document and Company Information [Abstract] Document and Company Information [Abstract] Document And Company Information. Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Investment income, net Investment Income, Nonoperating Corporate investments Marketable Securities, Current, Total Marketable Securities, Current Interest receivable Interest Receivable, Current Prepaid expenses and other current assets Other Assets, Current Long-term corporate investments Marketable Securities, Noncurrent, Total Marketable Securities, Noncurrent Litigation reserve Litigation Reserve, Current Accrued income taxes Accrued Income Taxes, Noncurrent Amortization of premiums and discounts on available-for-sale securities Accretion (Amortization) of Discounts and Premiums, Investments Prepaid expenses and other current assets Increase (Decrease) in Prepaid, Deferred Expense and Other Assets, Total Increase (Decrease) in Prepaid, Deferred Expense and Other Assets Accounts payable and other current liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities, Total Increase (Decrease) in Accounts Payable and Accrued Liabilities Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from and excess tax benefit related to exercise of stock options Proceeds from and excess tax benefit related to exercise of stock options Proceeds from and excess tax benefit related to exercise of stock options. Proceeds from and excess tax benefit related to exercise of stock options Purchases of available-for-sale securities Purchases of property and equipment Purchases of other assets Dividends paid Operating expenses Operating Costs and Expenses Basic and Diluted Earnings Per Share [Abstract] Basic and Diluted Earnings Per Share [Abstract] Property and Equipment Net of Accumulated Depreciation [Abstract] Property and Equipment, Net of Accumulated Depreciation [Abstract] Provision for deferred income taxes Income taxes Income Tax Expense (Benefit) Income taxes Total expenses Costs and Expenses Selling, general and administrative expenses Selling, General and Administrative Expense Operating expenses Operating expenses Operating income Common stock, $0.01 par value; Authorized: 600,000 shares; Issued and outstanding: 361,407 shares as of November 30, 2009 and 360,976 shares as of May 31, 2009, respectively Common Stock, Value, Issued, Total Common Stock, Value, Issued, Beginning Balance Common Stock, Value, Issued, Ending Balance Fair Value Measurements [Abstract] Fair Value Measurements [Abstract] Fair Value Measurements Abstract. Fair Value Measurements Fair Value Disclosures [Text Block] Balance Sheets [Abstract] Balance Sheets [Abstract] Statements of Income [Abstract] Statements of Income [Abstract] Statements of Cash Flows [Abstract] Statements of Cash Flows [Abstract] Comprehensive Income [Abstract] Comprehensive Income [Abstract] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Statement [Table] Statement [Line Items] Assets Commitments and Contingencies 2009 Accumulated Other Comprehensive Income (Loss), Net of Tax Stockholders' Equity Attributable to Parent Net Cash Provided by (Used in) Financing Activities Deferred income taxes Deferred income taxes Deferred income taxes Deferred income taxes COMMITMENTS AND CONTINGENCIES - NOTE I Proceeds from sale of business Proceeds from Divestiture of Businesses Basic and Diluted Earnings Per Share Property and Equipment, Net of Accumulated Depreciation Goodwill and Intangible Assets, Net of Accumulated Amortization Comprehensive Income Commitments and Contingencies Related Party Transactions