CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019
Cash Flows From Operating Activities:
Net Income (Loss)		$ (777,954)	$ 85,730
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Amortization of premiums, discounts, and securities issuance costs, net		4,083	144
Depreciation and amortization of non-financial assets		8,962	696
Originations of held-for-sale loans		(457,510)	(84,924)
Purchases of held-for-sale loans		(2,720,245)	(2,534,886)
Proceeds from sales of held-for-sale loans		3,126,860	2,123,794
Principal payments on held-for-sale loans		48,901	49,894
Net settlements of derivatives		(183,373)	(25,751)
Non-cash equity award compensation expense		7,240	7,255
Goodwill impairment expense		88,675	0
Market valuation adjustments		765,647	(48,172)
Realized gains, net		(29,817)	(13,513)
Net change in:
Accrued interest receivable and other assets		254,368	(108,985)
Accrued interest payable and accrued expenses and other liabilities		(80,219)	(9,744)
Net cash provided by (used in) operating activities		55,618	(558,462)
Cash Flows From Investing Activities:
Originations of loan investments		(263,544)	(84,638)
Purchases of loan investment		0	(49,489)
Proceeds from sales of loan investments		1,574,160	2,780
Principal payments on loan investments		1,136,000	619,085
Purchases of real estate securities		(52,260)	(242,970)
Purchases of multifamily securities held in consolidated securitization trusts		0	(68,601)
Sales of multifamily securities held in consolidated securitization trusts		142,990	0
Proceeds from sales of real estate securities		621,730	241,217
Principal payments on real estate securities		16,405	39,041
Purchases of servicer advance investments		(179,419)	(68,976)
Principal repayments from servicer advance investments		75,478	111,662
Acquisition of 5 Arches, net of cash acquired		0	(3,714)
Net investment in participation in loan warehouse facility		0	38,209
Net investment in multifamily loan fund		10,203	(28,673)
Other investing activities, net		(21,342)	(7,616)
Net cash provided by investing activities		3,060,401	497,317
Cash Flows From Financing Activities:
Proceeds from borrowings on short-term debt		3,655,530	2,731,731
Repayments on short-term debt		(5,322,519)	(2,675,308)
Proceeds from issuance of asset-backed securities		827,644	330,534
Repayments on asset-backed securities issued		(673,323)	(416,789)
Proceeds from issuance of long-term debt		944,282	0
Deferred long-term debt issuance costs paid		(7,830)	0
Repayments on long-term debt		(2,128,805)	0
Net settlements of derivatives		(84,336)	0
Net proceeds from issuance of common stock		5,707	198,333
Taxes paid on equity award distributions		(2,934)	0
Dividends paid		(51,810)	(59,868)
Other financing activities, net		4,650	(467)
Net cash (used in) provided by financing activities		(2,833,744)	108,166
Net increase in cash, cash equivalents and restricted cash		282,275	47,021
Cash, cash equivalents and restricted cash at beginning of period	[1]	290,833	205,077
Cash, cash equivalents, and restricted cash at end of period	[1]	573,108	252,098
Cash paid during the period for:
Interest		267,787	203,086
Taxes		209	4,158
Supplemental Noncash Information:
Real estate securities retained from loan securitizations		46,560	5,462
Retention of mortgage servicing rights from loan securitizations and sales		0	868
(Deconsolidation) consolidation of multifamily loans held in securitization trusts		(3,849,779)	1,481,554
(Deconsolidation) consolidation of multifamily ABS		(3,706,789)	1,408,002
Transfers from loans held-for-sale to loans held-for-investment		706,775	518,521
Transfers from residential loans to real estate owned		9,645	5,098
Right-of-use asset obtained in exchange for operating lease liability		$ 5,362	$ 13,016

[1] Cash, cash equivalents, and restricted cash at June 30, 2020 includes cash and cash equivalents of $529 million and restricted cash of $44 million, and at December 31, 2019 includes cash and cash equivalents of $197 million and restricted cash of $94 million.