Fair Value Measurements (Tables)

3 Months Ended

Jun. 30, 2012

Fair Value Measurements [Abstract]

Assets and liabilities measured at fair value on a recurring basis

	June 30, 2012
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	336	$	—	$	—	$	336
Marketable Securities:
Municipal commercial paper and demand notes		—		52,055		—		52,055
Corporate commercial paper		—		31,153		—		31,153
Holdings of New GM Securities:
New GM Common Stock		586,862		—		—		586,862
New GM Warrants		481,602		—		—		481,602
Total Assets	$	1,068,800	$	83,208	$	—	$	1,152,008
Liabilities:
Liquidating distributions payable	$	39,711	$	—	$	—	$	39,711
	March 31, 2012
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	38,396	$	—	$	—	$	38,396
Marketable Securities:
Municipal commercial paper and demand notes		—		25,253		—		25,253
Corporate commercial paper		—		59,317		—		59,317
U.S. government agency bonds		—		2,001		—		2,001
Holdings of New GM Securities:
New GM Common Stock		770,389		—		—		770,389
New GM Warrants		759,873		—		—		759,873
Total Assets	$	1,568,658	$	86,571	$	—	$	1,655,229
Liabilities:
Liquidating distributions payable	$	31,720	$	—	$	—	$	31,720