Net Assets in Liquidation - Additional Information (Detail)		6 Months Ended
	Mar. 31, 2011 USD ($) Unit	Sep. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)
Net Assets in Liquidation [Line Items]
Distributable Assets		$ 465,300,000
Cash and cash equivalents and marketable securities		510,900,000
Liquidating distributions payable in Distributable Cash for Excess GUC Trust Distributable Assets		7,000,000
Distributable Cash set aside for projected Trust fees, costs and expenses		31,000,000
Distributable cash pending distribution or set aside and not available for distribution		39,800,000
Accrued investment income		6,500,000	$ 3,400,000
Accrued reimbursements of legal fees		1,500,000
Number of Trust Units issued per thousand dollars of allowed general unsecured claims | Unit	1
Amount required to issue one Trust Unit per contingent rights	$ 1,000
Liquidation Basis of Accounting [Member]
Net Assets in Liquidation [Line Items]
Liquidating distributions payable		8,790,000	9,205,000
Accrued investment income		$ 7,347,000	$ 3,698,000