Loans Receivable - Activity Relating to Loans Receivable (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred origination fees and expenses	$ (7,121)
Amortization of deferred fees and expenses	(3,470)
Unrealized loss on foreign currency translation	36
Net Book Value [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
December 31, 2013	2,047,223
Loan fundings	740,236
Loan repayments and sales	(72,850)
Deferred origination fees and expenses	(7,121)
Amortization of deferred fees and expenses	3,470
Unrealized loss on foreign currency translation	(799)
March 31, 2014	2,710,159
Deferred Fees and Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
December 31, 2013	(29,188)
Loan fundings
Loan repayments and sales
Deferred origination fees and expenses	(7,121)
Amortization of deferred fees and expenses	3,470
Unrealized loss on foreign currency translation	(799)
March 31, 2014	(33,638)
Principal Balance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
December 31, 2013	2,076,411
Loan fundings	740,236
Loan repayments and sales	(72,850)
Deferred origination fees and expenses
Amortization of deferred fees and expenses
Unrealized loss on foreign currency translation
March 31, 2014	$ 2,743,797