Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		8 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Cash flows from operating activities
Net income	$ 52,841	$ 51,437		$ 153,400	$ 163,297
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of origination fees on loans receivable, net				(18,677)	(22,240)
Accretion of origination fees on interests in loans receivable, net				(849)	(227)
Amortization of financing costs	5,302	4,409		16,277	14,211
Non-cash equity compensation				(376)	7,354
Other income				(5,855)
Depreciation on real estate owned	1,940		$ 5,173	5,173
Gain on foreclosure of real estate owned				(1,430)
Non-cash advances to loans receivable in lieu of interest				(55,792)	(66,470)
Non-cash advances to interests in loans receivable in lieu of interest				(15,149)	(9,458)
Non-cash advances on secured financings in lieu of interest				15,161	14,748
Repayment of non-cash advances to loans receivable in lieu of interest				97,087	4,383
Repayment of non-cash advances to interests in loans receivable in lieu of interest				363	(4,383)
Repayment of non-cash advances to secured financings in lieu of interest				(22,285)
Realized loss on sale of investments		202			202
Reversal of current expected credit loss reserve	(9,306)			(17,413)
Changes in operating assets and liabilities:
Accrued interest receivable				5,163	(6,377)
Other assets				(18,519)	(777)
Accounts payable and accrued expenses				8,624	(333)
Interest payable				(1,507)	(807)
Deposits held				1,389	(519)
Due to/from affiliate					(25)
Management fee payable - affiliate				(60)	973
Incentive fee payable - affiliate				(187)	(2,096)
Net cash provided by operating activities				144,538	95,839
Net cash provided by operating activities				144,538	95,839
Cash flows from investing activities
Loan originations, acquisitions and advances, net of fees				(1,272,396)	(627,130)
Acquisitions and advances of interests in loans receivable, net of fees				(86,022)	(83,963)
Repayments of loans receivable				1,046,111	449,813
Repayments of interests in loans receivable				2,977	15,224
Exit fees received from loans receivable				5,698	1,172
Extension fees received from loans receivable				2,368	1,044
Cash, cash equivalents and restricted cash from foreclosure of properties				9,580
Acquisition of real estate owned				(11,463)
Sale of loans receivable					19,781
Reserves held for loans receivable				659	(2,880)
Net cash used in investing activities				(302,488)	(226,939)
Net cash used in investing activities				(302,488)	(226,939)
Cash flows from financing activities
Proceeds from issuance of common stock					70,000
Contributions from non-controlling interests				1,975
Offering costs				(30)	(947)
Dividends paid on common stock and vested restricted stock units				(141,792)	(160,301)
Dividends paid on redeemable common stock				(8,208)	(9,699)
Dividends paid on preferred stock				(8)	(16)
Distributions to non-controlling interests					(15,537)
Proceeds from secured financings				1,014,627	719,010
Payment of financing costs				(14,335)	(16,283)
Payment of exit fees on secured financings				(443)	(105)
Repayments of secured financings				(849,141)	(481,414)
Repayments of secured term loan				(5,837)	(3,375)
Repayments of debt related to real estate owned				(10,000)
Net cash provided by (used in) financing activities				(13,192)	101,333
Net decrease in cash, cash equivalents and restricted cash				(171,142)	(29,767)
Cash, cash equivalents and restricted cash, beginning of period				430,974	338,018	$ 338,018
Cash, cash equivalents and restricted cash, end of period	259,832	308,251	259,832	259,832	308,251	430,974
Cash and cash equivalents, beginning of period				427,512	334,999	334,999
Restricted cash, beginning of period				3,462	3,019	3,019
Cash and cash equivalents, end of period	235,596	304,692	235,596	235,596	304,692	427,512
Restricted cash, end of period	$ 24,236	$ 3,559	$ 24,236	24,236	3,559	$ 3,462
Supplemental disclosure of cash flow information:
Cash paid for interest				121,257	100,929
Supplemental disclosure of non-cash investing and financing activities:
Dividends accrued on common stock, redeemable common stock and vested restricted stock units				50,000	50,000
Dividends accrued on preferred stock				4	8
Dividends accrued on unvested restricted stock units				3,192	4,033
Loan principal payments held by servicer				252,946
Accrued financing costs				6,251	36
Accrued offering costs				2,231	$ 3,403
Working capital consolidated				(18,546)
Settlement of loan receivable				(103,901)
Real estate acquired in settlement of loan receivable				414,000
Assumption of debt related to real estate owned				(300,000)
Conversion of restricted stock units to common shares - common stock				6
Conversion of restricted stock units to common shares - additional paid in capital				$ (6)