Debt Obligations (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Accretable Yield Movement on Acquired Securitized Financings
Balance at the beginning of the period	$ 24,634	$ 31,346	$ 26,032	$ 0
Additions	0	0	0	32,072
Accretion	(1,345)	(1,567)	(2,743)	(2,293)
Reclassifications from nonaccretable discount	390	0	390	0
Balance at the end of the period	$ 23,679	$ 29,779	$ 23,679	$ 29,779