Segment Information - Statements of Income (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)
Segment Information
Interest income	$ 259,778	$ 125,480	$ 627,804	$ 321,772
Interest expense	160,452	55,560	350,079	144,122
Net interest income	99,326	69,920	277,725	177,650
Other revenue:
Gain on sales, including fee-based services, net	14,360	16,334	32,526	86,102
Mortgage servicing rights	19,408	32,453	52,287	95,688
Servicing revenue	37,526	34,960	109,045	94,683
Amortization of MSRs	(14,782)	(14,872)	(44,532)	(43,744)
Property operating income	445		1,031
(Loss) gain on derivative instruments, net	(15,909)	(1,492)	10,083	(7,320)
Other income, net	(6,014)	2,195	(16,061)	4,140
Total other revenue	35,034	69,578	144,379	229,549
Other expenses:
Employee compensation and benefits	38,811	41,973	119,736	128,647
Selling and administrative	13,225	11,757	40,960	33,707
Property operating expenses	366	149	1,443	421
Depreciation and amortization	2,078	1,807	6,092	5,349
Provision for loss sharing (net of recoveries)	412	(3,272)	(2,199)	(1,070)
Provision for credit losses (net of recoveries)	2,274	(3,799)	9,700	(12,689)
Total other expenses	57,166	48,615	175,732	154,365
Income before extinguishment of debt, sale of real estate, income from equity affiliates and income taxes	77,194	90,883	246,372	252,834
Loss on extinguishment of debt	(3,262)		(4,612)	(1,370)
Gain on sale of real estate				1,228
Income from equity affiliates	4,748	5,086	18,507	32,095
Benefit from (provision for) income taxes	374	(9,905)	(13,166)	(33,356)
Net income	79,054	86,064	247,101	251,431
Preferred stock dividends	10,342	4,913	30,612	13,216
Net income attributable to noncontrolling interest	6,002	8,347	19,811	26,806
Net income attributable to common stockholders	62,710	72,804	$ 196,678	211,409
Reporting segments | segment			2
Operating segments | Structured Business
Segment Information
Interest income	249,539	114,710	$ 597,847	294,418
Interest expense	157,325	50,823	338,692	131,795
Net interest income	92,214	63,887	259,155	162,623
Other revenue:
Property operating income	445		1,031
Other income, net	1,763	2,168	(4,370)	4,105
Total other revenue	2,208	2,168	(3,339)	4,105
Other expenses:
Employee compensation and benefits	13,342	14,082	42,694	37,566
Selling and administrative	5,961	5,718	19,799	15,477
Property operating expenses	366	149	1,443	421
Depreciation and amortization	906	634	2,574	1,832
Provision for credit losses (net of recoveries)	2,206	(3,445)	9,363	(12,807)
Total other expenses	22,781	17,138	75,873	42,489
Income before extinguishment of debt, sale of real estate, income from equity affiliates and income taxes	71,641	48,917	179,943	124,239
Loss on extinguishment of debt	(3,262)		(4,612)	(1,370)
Income from equity affiliates	4,748	5,086	18,507	32,095
Benefit from (provision for) income taxes	319	(622)	(1,368)	(6,288)
Net income	73,446	53,381	192,470	148,676
Preferred stock dividends	10,342	4,913	30,612	13,216
Net income attributable to common stockholders	63,104	48,468	161,858	135,460
Operating segments | Agency Business
Segment Information
Interest income	10,239	10,770	29,957	27,354
Interest expense	3,127	4,737	11,387	12,327
Net interest income	7,112	6,033	18,570	15,027
Other revenue:
Gain on sales, including fee-based services, net	14,360	16,334	32,526	86,102
Mortgage servicing rights	19,408	32,453	52,287	95,688
Servicing revenue	37,526	34,960	109,045	94,683
Amortization of MSRs	(14,782)	(14,872)	(44,532)	(43,744)
(Loss) gain on derivative instruments, net	(15,909)	(1,492)	10,083	(7,320)
Other income, net	(7,777)	27	(11,691)	35
Total other revenue	32,826	67,410	147,718	225,444
Other expenses:
Employee compensation and benefits	25,469	27,891	77,042	91,081
Selling and administrative	7,264	6,039	21,161	18,230
Depreciation and amortization	1,172	1,173	3,518	3,517
Provision for loss sharing (net of recoveries)	412	(3,272)	(2,199)	(1,070)
Provision for credit losses (net of recoveries)	68	(354)	337	118
Total other expenses	34,385	31,477	99,859	111,876
Income before extinguishment of debt, sale of real estate, income from equity affiliates and income taxes	5,553	41,966	66,429	128,595
Gain on sale of real estate				1,228
Benefit from (provision for) income taxes	55	(9,283)	(11,798)	(27,068)
Net income	5,608	32,683	54,631	102,755
Net income attributable to common stockholders	5,608	32,683	54,631	102,755
Other / Eliminations
Other expenses:
Net income attributable to noncontrolling interest	6,002	8,347	19,811	26,806
Net income attributable to common stockholders	$ (6,002)	$ (8,347)	$ (19,811)	$ (26,806)