Reserves for Expected Costs of Liquidation and Residual Wind-Down Claims - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Restructuring Cost and Reserve [Line Items]
Expected liquidation date			Oct. 31, 2016
Reserve for Expected Wind-Down Costs [Member]
Restructuring Cost and Reserve [Line Items]
Net increase (decrease in) additions to reserves for Expected Costs of Liquidation	$ 2,200,000	$ (4,200,000)	$ 4,700,000	$ (4,100,000)
Reserve for Expected Reporting Costs [Member]
Restructuring Cost and Reserve [Line Items]
Net increase (decrease in) additions to reserves for Expected Costs of Liquidation	$ 51,000.0	$ (2,300,000)	$ (500,000)	$ (4,100,000)