Fair Value of Financial Instruments - Equity Interest in Ernest and Related Loans Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Financial Instruments Measured At Fair Value On Recurring Basis [Line Items]
Fair Value	$ 200,750
Cost	200,750
Fair Value Measurements, Recurring [Member] | Acquisition loans [Member] | Other loans [Member]
Financial Instruments Measured At Fair Value On Recurring Basis [Line Items]
Fair Value	97,450
Cost	97,450
Fair Value Measurements, Recurring [Member] | Equity investments [Member] | Other assets [Member]
Financial Instruments Measured At Fair Value On Recurring Basis [Line Items]
Fair Value	3,300
Cost	3,300
Fair Value Measurements, Recurring [Member] | Mortgage loans [Member] | Mortgage loans [Member]
Financial Instruments Measured At Fair Value On Recurring Basis [Line Items]
Fair Value	100,000
Cost	$ 100,000