Income Tax Provision - Summary of Deferred Taxes (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014
Deferred tax assets:
Reserves for expected costs of liquidation	$ 12,555
Net operating and capital loss carryovers	106,526
Gross deferred tax assets	119,081
Less: Valuation allowance	(40,895)
Deferred tax asset, net of valuation allowance	78,186
Deferred tax liabilities:
Fair value in excess of tax basis of holdings of New GM Securities	(76,311)
Other	(1,875)
Gross deferred tax liabilities	(78,186)
Net deferred tax liability	$ 0