Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net income	$ 211,885	$ 100,494	$ 25,424
Adjustments to reconcile net income to net cash provided by operating activities
Gain on investments at fair value	(21,967)	(13,258)	(7,417)
Income from equity investments in unconsolidated subsidiaries	(11,798)	(28,036)
Non-cash compensation expense	20,717	9,716	6,204
Distributions of income from unconsolidated subsidiaries	5,007	17,867	8,795
Amortization of deferred fees and other items on loans	(36,053)	(19,785)	(6,290)
Amortization of deferred financing costs and other items on debt obligations	20,708	9,900	4,935
Loss on deconsolidation of subsidiary		8,615
Valuation allowance on loans held-for-sale			(1,259)
Changes in assets and liabilities, net
Other assets	(22,385)	(13,166)	116
Accounts payable, accrued expenses, and other liabilities	5,280	8,290	(1,839)
Net cash provided by operating activities	171,394	80,637	28,669
Cash flows from investing activities
Origination and fundings of loans receivable	(7,204,487)	(3,067,263)	(2,327,913)
Principal collections and proceeds from the sale of loans receivable and other assets	2,347,966	620,413	508,718
Origination and exit fees received on loans receivable	33,501	35,449	25,402
Change in restricted cash	2,035	(1,495)	4,151
Distributions from equity investments			7,151
Net cash used in investing activities	(4,820,985)	(2,412,896)	(1,782,491)
Cash flows from financing activities
Borrowings under secured debt agreements	6,885,393	3,196,939	1,667,623
Repayments under secured debt agreements	(3,030,091)	(1,926,644)	(578,484)
Proceeds from sale of loan participations	256,000	494,306	90,000
Repayment of loan participations	(238,164)	(61,836)
Proceeds from issuance of convertible notes			168,415
Repayment and purchase of secured notes			(11,059)
Payment of deferred financing costs	(21,230)	(16,160)	(8,867)
Receipts (payments) under derivative financial instruments	17,076		(6,123)
Net proceeds from issuance of class A common stock	1,029,540	766,138	633,807
Dividends paid on class A common stock	(166,978)	(84,238)	(7,776)
Contributions from non-controlling interests			15,000
Distributions to non-controlling interests	(37,428)	(13,775)	(72,853)
Repayment of other liabilities		(20,794)	(98,965)
Net cash provided by financing activities	4,694,118	2,333,936	1,790,718
Net increase in cash and cash equivalents	44,527	1,677	36,896
Cash and cash equivalents at beginning of year	51,810	52,342	15,423
Effects of currency translation on cash and cash equivalents	113	(2,209)	23
Cash and cash equivalents at end of year	96,450	51,810	52,342
Supplemental disclosure of cash flows information
Payments of interest	(127,429)	(55,174)	(12,702)
(Payments) receipts of income taxes	(125)	(1,473)	8
Supplemental disclosure of non-cash investing and financing activities
Dividends declared, not paid	(58,095)	(30,357)	(13,302)
Participations sold, net	17,836	432,470	90,000
Deconsolidation (consolidation) of subsidiaries		$ 8,615	(38,913)
Loan principal payments held by servicer	$ 118,074		$ 7,798