Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims - Summary of Activity in Reserves for Expected Costs of Liquidation (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 32,902	$ 33,347	$ 31,278	$ 36,486
Plus additions to (reductions in) reserves	(2,474)	3,200	7,824	7,335
Less liquidation costs incurred :
Ending Balance	27,593	32,632	27,593	32,632
Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(1,452)	(2,432)	(6,331)	(6,758)
Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(1,287)	(1,368)	(4,081)	(4,156)
Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(96)	(115)	(1,097)	(275)
Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	22,176	22,042	21,089	22,529
Plus additions to (reductions in) reserves	(1,555)	2,952	5,640	7,629
Less liquidation costs incurred :
Ending Balance	18,699	22,086	18,699	22,086
Reserve for Expected Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(1,093)	(1,997)	(4,474)	(5,324)
Reserve for Expected Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(816)	(899)	(2,675)	(2,728)
Reserve for Expected Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(13)	(12)	(881)	(20)
Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	9,178	9,663	8,602	12,235
Plus additions to (reductions in) reserves	(919)	248	2,184	(294)
Less liquidation costs incurred :
Ending Balance	7,368	8,926	7,368	8,926
Reserve for Expected Reporting Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(358)	(431)	(1,852)	(1,406)
Reserve for Expected Reporting Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(450)	(451)	(1,350)	(1,354)
Reserve for Expected Reporting Costs [Member] | Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred :
Liquidation costs incurred	(83)	(103)	(216)	(255)
Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	329	408	364	464
Less liquidation costs incurred :
Ending Balance	308	390	308	390
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	(21)	(18)	(56)	(74)
Reserve for Residual Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,219	1,234	1,223	1,258
Less liquidation costs incurred :
Ending Balance	1,218	1,230	1,218	1,230
Reserve for Residual Wind-Down Costs [Member] | Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred :
Liquidation costs incurred	$ (1)	$ (4)	$ (5)	$ (28)