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	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period			$ 177
Plus addition to reserves
Balance, end of period	$ 178		178
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	178	169	177	169
Plus addition to reserves			1
Balance, end of period	$ 178	$ 169	$ 178	$ 169