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
	Jun. 30, 2015	Jun. 30, 2014
Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Plus additions to (reductions in) reserves	$ 1,400	$ 2,400
Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Plus additions to (reductions in) reserves	900	(600)
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	31,278	36,486
Plus additions to (reductions in) reserves	2,331	1,844
Less liquidation costs incurred:
Ending Balance	30,118	34,680
Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(2,120)	(2,131)
Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(1,285)	(1,388)
Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(86)	(131)
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	21,089	22,529
Plus additions to (reductions in) reserves	1,447	2,437
Less liquidation costs incurred:
Ending Balance	20,344	22,513
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(1,364)	(1,526)
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(818)	(917)
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(10)	(10)
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	8,602	12,235
Plus additions to (reductions in) reserves	884	(593)
Less liquidation costs incurred:
Ending Balance	8,206	10,483
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(754)	(585)
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(450)	(453)
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(76)	(121)
Liquidation Basis of Accounting [Member] | Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	364	464
Less liquidation costs incurred:
Ending Balance	347	446
Liquidation Basis of Accounting [Member] | Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred:
Liquidation costs incurred	(17)	(18)
Liquidation Basis of Accounting [Member] | Reserve for Residual Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,223	1,258
Less liquidation costs incurred:
Ending Balance	1,221	1,238
Liquidation Basis of Accounting [Member] | Reserve for Residual Wind-Down Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred:
Liquidation costs incurred	$ (2)	$ (20)