Loans, Notes and Certificates Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 781,215	$ 1,829,042
Fair Value	785,316	1,839,990
Fair Value, Measurements, Recurring | Notes And Certificates At Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate principal balance outstanding	795,842	1,859,982
Fair valuation adjustments	(10,526)	(19,992)
Fair Value	785,316	1,839,990
Fair Value, Measurements, Recurring | Loans at Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate principal balance outstanding	791,774	1,849,042
Fair valuation adjustments	(10,559)	(20,000)
Fair Value	$ 781,215	$ 1,829,042