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) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Restructuring Cost and Reserve [Line Items]
Balance, beginning of year	$ 169
Balance, end of year	177	$ 169
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of year	169	169	$ 966
Plus addition to reserves	8		9
Plus reclassification of accrued liability			9
Less claims allowed during the period			(815)
Balance, end of year	$ 177	$ 169	$ 169