Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured	$ 1,442,475,000		$ 1,442,475,000		$ 1,668,260,000
Liquidating distributions payable	8,466,000		8,466,000		16,555,000
Transfers between fair value amount	0	0	0	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured	0		0		0
Liquidating distributions payable	$ 0		$ 0		$ 0