Holdings of New GM Securities - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended
	Aug. 05, 2015	Jun. 30, 2015	Mar. 31, 2015
Distribution Made to Limited Partner [Line Items]
Liquidating distributions payable in cash		$ 400
New GM Securities reserved and set aside for projected GUC Trust fees, costs and expenses		53,500
New GM Securities set aside for potential Taxes on Distribution		252,400
Projected Dividend Taxes		7,400
Liquidation Basis of Accounting [Member]
Distribution Made to Limited Partner [Line Items]
Liquidating distributions payable		$ 14,645	$ 7,714
New GM Common Stock [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution		204,336
Number of securities set aside from distribution		4,406,295
New GM Common Stock [Member] | Subsequent Event [Member]
Distribution Made to Limited Partner [Line Items]
Gross proceeds from the liquidation of New GM Securities	$ 742,500
Net proceeds from the liquidation of New GM Securities	$ 741,700
New GM Series A Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution		185,686
Number of warrants set aside from distribution		4,005,697
New GM Series B Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution		185,686
Number of warrants set aside from distribution		4,005,697
New GM Securities [Member]
Distribution Made to Limited Partner [Line Items]
Liquidating distributions payable		$ 14,200