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	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of year	$ 28,698	$ 30,855	$ 32,247
Less claims allowed during the year	(3,292)	(2,157)	(1,392)
Balance, end of year	$ 25,406	$ 28,698	$ 30,855