Loans - Schedule of Company's Residential Mortgage Loan Portfolio and Commercial Loan Portfolio (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2024	Dec. 31, 2023
Securitized Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan receivable, weighted average yield, fair value of underlying loans	5.21%
Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value	$ 265,047	$ 317,631
Residential Mortgage \| Securitized Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value	6,226,698	5,358,281
Residential Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	6,701,366	6,124,045
Premium (Discount)	(15,705)	(46,975)
Amortized Cost	6,685,661	6,077,070
Gross Unrealized Gains	78,811	38,280
Gross Unrealized Losses	(272,727)	(439,438)
Fair Value	$ 6,491,745	$ 5,675,912
Weighted Average Coupon	5.69%	5.28%
Weighted Average Yield	5.73%	5.68%
Weighted Average Life (Years)	8 years 5 months 26 days	9 years 10 months 9 days
Residential Portfolio Segment \| Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 255,983	$ 306,987
Premium (Discount)	5,586	2,740
Amortized Cost	261,569	309,727
Gross Unrealized Gains	3,976	8,478
Gross Unrealized Losses	(498)	(574)
Fair Value	$ 265,047	$ 317,631
Weighted Average Coupon	9.19%	7.99%
Weighted Average Yield	8.46%	8.08%
Weighted Average Life (Years)	3 years 11 months 19 days	3 years 3 months 14 days
Loan receivable, weighted average yield, fair value of underlying loans	8.90%
Residential Portfolio Segment \| Residential Mortgage \| Securitized Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 6,445,383	$ 5,817,058
Premium (Discount)	(21,291)	(49,715)
Amortized Cost	6,424,092	5,767,343
Gross Unrealized Gains	74,835	29,802
Gross Unrealized Losses	(272,229)	(438,864)
Fair Value	$ 6,226,698	$ 5,358,281
Weighted Average Coupon	5.55%	5.14%
Weighted Average Yield	5.62%	5.54%
Weighted Average Life (Years)	8 years 8 months 1 day	10 years 2 months 15 days
Loan receivable, weighted average yield, fair value of underlying loans	5.70%
Residential Portfolio Segment \| Non-Agency Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 14,018	$ 92,033
Premium (Discount)	(248)	835
Amortized Cost	13,770	92,868
Gross Unrealized Gains	133	2,222
Gross Unrealized Losses	(498)	(574)
Fair Value	$ 13,405	$ 94,516
Weighted Average Coupon	7.57%	8.10%
Weighted Average Yield	4.52%	7.29%
Weighted Average Life (Years)	3 years 7 months 9 days	3 years 1 month 20 days
Residential Portfolio Segment \| Non-Agency Loans \| Securitized Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 6,242,559	$ 5,599,960
Premium (Discount)	(6,609)	(32,250)
Amortized Cost	6,235,950	5,567,710
Gross Unrealized Gains	74,835	29,603
Gross Unrealized Losses	(258,620)	(422,144)
Fair Value	$ 6,052,165	$ 5,175,169
Weighted Average Coupon	5.60%	5.19%
Weighted Average Yield	5.60%	5.51%
Weighted Average Life (Years)	8 years 9 months 7 days	10 years 4 months 13 days
Loan receivable, weighted average yield, fair value of underlying loans	5.69%
Residential Portfolio Segment \| Re- and Non-Performing Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 2,094	$ 2,604
Premium (Discount)	(1,234)	(1,630)
Amortized Cost	860	974
Gross Unrealized Gains	1,107	1,432
Gross Unrealized Losses	0	0
Fair Value	$ 1,967	$ 2,406
Weighted Average Yield	111.21%	112.97%
Weighted Average Life (Years)	1 year 5 months 15 days	1 year 8 months 8 days
Residential Portfolio Segment \| Re- and Non-Performing Loans \| Securitized Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 202,824	$ 217,098
Premium (Discount)	(14,682)	(17,465)
Amortized Cost	188,142	199,633
Gross Unrealized Gains	0	199
Gross Unrealized Losses	(13,609)	(16,720)
Fair Value	$ 174,533	$ 183,112
Weighted Average Coupon	3.95%	3.88%
Weighted Average Yield	6.10%	6.30%
Weighted Average Life (Years)	5 years 8 months 15 days	6 years 1 month 6 days
Loan receivable, weighted average yield, fair value of underlying loans	6.15%
Residential Portfolio Segment \| Agency-Eligible Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 109,219	$ 212,350
Premium (Discount)	2,448	3,535
Amortized Cost	111,667	215,885
Gross Unrealized Gains	1,154	4,824
Gross Unrealized Losses	0	0
Fair Value	$ 112,821	$ 220,709
Weighted Average Coupon	7.58%	7.94%
Weighted Average Yield	6.76%	7.28%
Weighted Average Life (Years)	3 years 8 months 23 days	3 years 4 months 13 days
Residential Portfolio Segment \| Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 130,652
Premium (Discount)	4,620
Amortized Cost	135,272
Gross Unrealized Gains	1,582
Gross Unrealized Losses	0
Fair Value	$ 136,854
Weighted Average Coupon	10.72%
Weighted Average Yield	9.62%
Weighted Average Life (Years)	4 years 3 months

The amount represents the loan receivables for weighted average coupon rate for the during period.

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Loan Receivable, Weighted Average Yield, Fair Value Of Underlying Loans

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The amount represent the loans receivable gross unrealized gains for the during period.

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The amount represent the loans receivable gross unrealized loss for the during period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unamortized purchase premium (discount) on financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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