Loans Receivable, Net - Activity Relating to Loans Receivable Portfolio (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance	$ 9,077,007
Loan originations, acquisitions, and fundings	3,151,882	$ 7,203,145	$ 3,067,263
Unrealized (loss) gain on foreign currency translation	(49,686)	(41,616)	(15,822)
Amortization of fees and other items	40,345	36,053	19,785
Ending Balance	8,692,978	9,077,007
Net Book Value [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance	9,077,007	4,428,500
Loan fundings	3,151,882
Loan originations, acquisitions, and fundings		7,203,145
Loan repayments	(3,374,622)	(2,407,920)
Unrealized (loss) gain on foreign currency translation	(156,937)	(149,269)
Deferred fees and other items	(44,697)	(33,501)
Amortization of fees and other items	40,345	36,052
Ending Balance	8,692,978	9,077,007	4,428,500
Deferred Fees/Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance	(31,354)	(34,397)
Unrealized (loss) gain on foreign currency translation	1,466	492
Deferred fees and other items	(44,697)	(33,501)
Amortization of fees and other items	40,345	36,052
Ending Balance	(34,240)	(31,354)	(34,397)
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance	9,108,361	4,462,897
Loan fundings	3,151,882
Loan originations, acquisitions, and fundings		7,203,145
Loan repayments	(3,374,622)	(2,407,920)
Unrealized (loss) gain on foreign currency translation	(158,403)	(149,761)
Ending Balance	$ 8,727,218	$ 9,108,361	$ 4,462,897