Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims and Costs - Summary of Activity in Reserves for Residual Wind-Down Claims and Costs (Detail) - Liquidation Basis of Accounting [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Restructuring Cost and Reserve [Line Items]
Balance, beginning of year	$ 966	$ 19,957	$ 26,629
Plus net addition to reserves	9	237
Plus reclassification of accrued liability	9	417
Less claims allowed during the period	(815)	(19,641)	(6,661)
Less costs incurred by trust professionals		(4)	(11)
Balance, end of year	$ 169	$ 966	$ 19,957