Quarterly report pursuant to Section 13 or 15(d)

Accumulated Other Comprehensive Income (Details)

v2.4.1.9
Accumulated Other Comprehensive Income (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Feb. 28, 2015
Feb. 28, 2014
Feb. 28, 2015
Feb. 28, 2014
Equity [Abstract]        
Accumulated other comprehensive income, Beginning balance $ 22.4us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax $ 13.7us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax $ 21.5us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax $ 22.0us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Other comprehensive (loss)/income:        
Unrealized (losses)/gains on available-for-sale securities, net of tax (0.6)us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax 11.0us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax 0.4us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax 2.9us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax
Reclassification adjustment for the net gain on sale of available-for-sale securities realized in net income, net of tax 0us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax (0.1)us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax (0.1)us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax (0.3)us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax
Total other comprehensive (loss)/income, net of tax (0.6)us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent 10.9us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent 0.3us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent 2.6us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Accumulated other comprehensive income, Ending balance 21.8us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 24.6us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 21.8us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 24.6us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Total tax expense included in other comprehensive (loss)/income $ 0us-gaap_OtherComprehensiveIncomeLossTax $ 6.5us-gaap_OtherComprehensiveIncomeLossTax $ 0.2us-gaap_OtherComprehensiveIncomeLossTax $ 1.7us-gaap_OtherComprehensiveIncomeLossTax