Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims - Summary of Activity in Reserves for Expected Costs of Liquidation (Detail) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Plus additions to (reductions in) reserves	$ 2,200,000	$ (4,200,000)	$ 4,700,000	$ (4,100,000)
Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Plus additions to (reductions in) reserves	51,000.0	(2,300,000)	(500,000)	(4,100,000)
Liquidation Basis of Accounting [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	34,680,000	53,601,000	36,486,000	61,513,000
Plus additions to (reductions in) reserves	2,291,000	(6,531,000)	4,135,000	(8,209,000)
Less liquidation costs incurred (net of reversals):
Ending Balance	33,347,000	43,107,000	33,347,000	43,107,000
Liquidation Basis of Accounting [Member] | Trust Professionals [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(2,195,000)	(2,427,000)	(4,326,000)	(7,091,000)
Liquidation Basis of Accounting [Member] | Trust Governance [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(1,400,000)	(1,480,000)	(2,788,000)	(2,910,000)
Liquidation Basis of Accounting [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(29,000)	(56,000)	(160,000)	(196,000)
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	22,513,000	33,594,000	22,529,000	38,043,000
Plus additions to (reductions in) reserves	2,240,000	(4,204,000)	4,677,000	(4,063,000)
Less liquidation costs incurred (net of reversals):
Ending Balance	22,042,000	26,468,000	22,042,000	26,468,000
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(1,801,000)	(1,878,000)	(3,327,000)	(5,482,000)
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(912,000)	(1,031,000)	(1,829,000)	(2,004,000)
Liquidation Basis of Accounting [Member] | Reserve for Expected Wind-Down Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	2,000	(13,000)	(8,000)	(26,000)
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	10,483,000	17,362,000	12,235,000	20,442,000
Plus additions to (reductions in) reserves	51,000	(2,327,000)	(542,000)	(4,146,000)
Less liquidation costs incurred (net of reversals):
Ending Balance	9,663,000	14,272,000	9,663,000	14,272,000
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(390,000)	(268,000)	(975,000)	(953,000)
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(450,000)	(452,000)	(903,000)	(901,000)
Liquidation Basis of Accounting [Member] | Reserve for Expected Reporting Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(31,000)	(43,000)	(152,000)	(170,000)
Liquidation Basis of Accounting [Member] | Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	446,000	491,000	464,000	499,000
Plus additions to (reductions in) reserves
Less liquidation costs incurred (net of reversals):
Ending Balance	408,000	494,000	408,000	494,000
Liquidation Basis of Accounting [Member] | Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred
Liquidation Basis of Accounting [Member] | Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(38,000)	3,000	(56,000)	(5,000)
Liquidation Basis of Accounting [Member] | Reserve for Indenture Trustee/Fiscal and Paying Agent Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred
Liquidation Basis of Accounting [Member] | Reserve for Avoidance Action Defense Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance		760,000		898,000
Plus additions to (reductions in) reserves
Less liquidation costs incurred (net of reversals):
Ending Balance		588,000		588,000
Liquidation Basis of Accounting [Member] | Reserve for Avoidance Action Defense Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred		(172,000)		(310,000)
Liquidation Basis of Accounting [Member] | Reserve for Avoidance Action Defense Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred
Liquidation Basis of Accounting [Member] | Reserve for Avoidance Action Defense Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred
Liquidation Basis of Accounting [Member] | Reserve for Residual Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,238,000	1,394,000	1,258,000	1,631,000
Plus additions to (reductions in) reserves
Less liquidation costs incurred (net of reversals):
Ending Balance	1,234,000	1,285,000	1,234,000	1,285,000
Liquidation Basis of Accounting [Member] | Reserve for Residual Wind-Down Costs [Member] | Trust Professionals [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred	(4,000)	(109,000)	(24,000)	(346,000)
Liquidation Basis of Accounting [Member] | Reserve for Residual Wind-Down Costs [Member] | Trust Governance [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred
Liquidation Basis of Accounting [Member] | Reserve for Residual Wind-Down Costs [Member] | Other Administrative Expenses [Member]
Less liquidation costs incurred (net of reversals):
Liquidation costs incurred