Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims - Summary of Activity in Reserves for Residual Wind-Down Claims (Detail) (Liquidation Basis of Accounting [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 28,335	$ 29,692	$ 28,698	$ 30,855
Less claims allowed during the period	(916)	(255)	(1,279)	(1,418)
Balance, end of period	$ 27,419	$ 29,437	$ 27,419	$ 29,437