Quarterly report pursuant to Section 13 or 15(d)

Accumulated Other Comprehensive Income/(Loss) (Details)

v2.4.1.9
Accumulated Other Comprehensive Income/(Loss) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Nov. 30, 2014
Nov. 30, 2013
Nov. 30, 2014
Nov. 30, 2013
Equity [Abstract]        
Accumulated other comprehensive income/(loss), Beginning balance $ 26.0us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax $ (4.9)us-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 (3.6)us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax 18.6us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax 1.0us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax (8.2)us-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 0us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax (0.1)us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax (0.1)us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax
Total other comprehensive (loss)/income, net of tax (3.6)us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent 18.6us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent 0.9us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent (8.3)us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Accumulated other comprehensive income/(loss), Ending balance 22.4us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 13.7us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 22.4us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 13.7us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Total tax (benefit)/expense included in other comprehensive (loss)/income $ (1.9)us-gaap_OtherComprehensiveIncomeLossTax $ 10.8us-gaap_OtherComprehensiveIncomeLossTax $ 0.2us-gaap_OtherComprehensiveIncomeLossTax $ (4.8)us-gaap_OtherComprehensiveIncomeLossTax