Quarterly report pursuant to Section 13 or 15(d)

Funds Held for Clients and Corporate Investments (Details 2)

v2.4.1.9
Funds Held for Clients and Corporate Investments (Details 2) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 9 Months Ended
Feb. 28, 2015
Security
Feb. 28, 2014
Feb. 28, 2015
Security
Feb. 28, 2014
May 31, 2014
Security
Maturity Date:          
Due in one year or less, Amortized cost $ 367.0us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis   $ 367.0us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis    
Due in one year or less, Fair value 369.2us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue   369.2us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue    
Due after one year through three years, Amortized cost 736.0payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearOneThroughThreeAmortizedCostBasis   736.0payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearOneThroughThreeAmortizedCostBasis    
Due after one year through three years, Fair value 747.6payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearOneThroughThreeFairValue   747.6payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearOneThroughThreeFairValue    
Due after three years through five years, Amortized cost 766.7payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearFourThroughFiveAmortizedCostBasis   766.7payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearFourThroughFiveAmortizedCostBasis    
Due after three years through five years, Fair value 775.0payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearFourThroughFiveFairValue   775.0payx_AvailableForSaleSecuritiesDebtMaturitiesRollingYearFourThroughFiveFairValue    
Due after five years, Amortized cost 1,277.8payx_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterFiveYearsAmortizedCost   1,277.8payx_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterFiveYearsAmortizedCost    
Due after five years, Fair value 1,291.3payx_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearFiveFairValue   1,291.3payx_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearFiveFairValue    
Total, Amortized cost 3,147.5us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis   3,147.5us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis    
Fair value 3,183.1us-gaap_AvailableForSaleSecurities   3,183.1us-gaap_AvailableForSaleSecurities   3,391.4us-gaap_AvailableForSaleSecurities
Funds Held for Clients and Corporate Investments (Textual)          
Net unrealized gain on available-for-sale securities 35.6payx_Netunrealizedgainlossonavailableforsalesecurities   35.6payx_Netunrealizedgainlossonavailableforsalesecurities   34.5payx_Netunrealizedgainlossonavailableforsalesecurities
Number of available-for-sale securities in an unrealized loss position 81us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1   81us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1   98us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
Gross realized gains 0us-gaap_AvailableForSaleSecuritiesGrossRealizedGains 0.3us-gaap_AvailableForSaleSecuritiesGrossRealizedGains 0.2us-gaap_AvailableForSaleSecuritiesGrossRealizedGains 0.5us-gaap_AvailableForSaleSecuritiesGrossRealizedGains  
Gross realized losses $ 0us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses $ 0us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses $ 0us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses $ 0us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses  
Minimum maturity period for VRDNs primarily categorized as due after five years (in years)     20 years    
Maximum maturity period for VRDNs, primarily categorized as due after five years (in years)     30 years