Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims and Costs - Summary of Activity in Reserves for Expected Costs of Liquidation (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 23,378	$ 31,683	$ 23,399	$ 30,055
Plus additions to (reductions in) reserves	6,910	(2,474)	11,953	7,824
Less funds returned to DIP Lenders	(6,000)		(6,000)
Less liquidation costs incurred:
Ending Balance	21,501	26,375	21,501	26,375
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance			23,399
Less liquidation costs incurred:
Ending Balance	21,501		21,501
Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(1,497)	(1,451)	(3,966)	(6,326)
Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(1,209)	(1,287)	(3,665)	(4,081)
Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(81)	(96)	(220)	(1,097)
Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	15,298	22,176	16,727	21,089
Plus additions to (reductions in) reserves	3,666	(1,555)	5,022	5,640
Less funds returned to DIP Lenders	(6,000)		(6,000)
Less liquidation costs incurred:
Ending Balance	11,241	18,699	11,241	18,699
Reserve for Expected Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(962)	(1,093)	(2,196)	(4,474)
Reserve for Expected Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(747)	(816)	(2,266)	(2,675)
Reserve for Expected Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(14)	(13)	(46)	(881)
Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	7,824	9,178	6,379	8,602
Plus additions to (reductions in) reserves	3,244	(919)	6,931	2,184
Less liquidation costs incurred:
Ending Balance	10,016	7,368	10,016	7,368
Reserve for Expected Reporting Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(535)	(358)	(1,770)	(1,852)
Reserve for Expected Reporting Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(450)	(450)	(1,350)	(1,350)
Reserve for Expected Reporting Costs [Member] | Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(67)	(83)	(174)	(216)
Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	256	329	293	364
Less liquidation costs incurred:
Ending Balance	244	308	244	308
Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	$ (12)	$ (21)	$ (49)	$ (56)