Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims and Costs - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Net increase (decrease in) additions to reserves for Expected Costs of Liquidation	$ (4,013)	$ (4,474)
Expected liquidation end date	Jan. 31, 2022
Reserves For Residual Wind Down Claims And Costs	$ 200
Legal Fees Reimbursement [Member]
Restructuring Cost and Reserve [Line Items]
Loss contingency Inestimable loss	10,000
Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Net increase (decrease in) additions to reserves for Expected Costs of Liquidation	(2,855)	(2,401)
Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Net increase (decrease in) additions to reserves for Expected Costs of Liquidation	$ (1,158)	$ (2,073)