Guarantees (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2013
Guarantor Obligations [Line Items]
Amounts guaranteed (not to exceed)	$ 250,455	$ 301,870	$ 126,608
Amounts outstanding under guarantee	208,316	218,847	121,634
Fair value of guarantees	7,272	7,344	6,023
Number of years, before expiring guarantees	1 year
Financial Guarantee [Member]
Guarantor Obligations [Line Items]
Amounts outstanding under guarantee	$ 1,368	$ 26,076	$ 3,200