Income Tax Benefit (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Jun. 30, 2011
Deferred tax assets:
Reserves for expected costs of liquidation	$ 21,106
Net operating losses	12,672
Tax basis in excess of fair value of holdings of New GM Securities	15,374
Deferred Tax Assets Tax Basis In Excess Of Fair Value Of Holdings Securities For Trust Beneficiaries	15,374
Total deferred tax assets	49,152
Valuation allowances	(49,152)	(18,300)
Net deferred tax asset