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	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 23,840	$ 28,335	$ 25,406	$ 28,698
Less claims allowed during the period	(2,349)	(916)	(3,915)	(1,279)
Balance, end of period	$ 21,491	$ 27,419	$ 21,491	$ 27,419