Secured Financing Agreements - Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Principal	$ 2,384,678	$ 2,432,115
Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Principal	2,403,678	2,444,091
Repurchase Agreements | Overnight
Assets Sold under Agreements to Repurchase [Line Items]
Principal	0	0
Repurchase Agreements | 1 to 29 days
Assets Sold under Agreements to Repurchase [Line Items]
Principal	259,229	272,490
Repurchase Agreements | 30 to 59 days
Assets Sold under Agreements to Repurchase [Line Items]
Principal	473,497	495,636
Repurchase Agreements | 60 to 89 days
Assets Sold under Agreements to Repurchase [Line Items]
Principal	194,024	305,426
Repurchase Agreements | 90 to 119 days
Assets Sold under Agreements to Repurchase [Line Items]
Principal	69,793	54,376
Repurchase Agreements | 120 to 180 days
Assets Sold under Agreements to Repurchase [Line Items]
Principal	187,582	105,727
Repurchase Agreements | 180 days to 1 year
Assets Sold under Agreements to Repurchase [Line Items]
Principal	616,005	39,620
Repurchase Agreements | 1 to 2 years
Assets Sold under Agreements to Repurchase [Line Items]
Principal	244,967	808,601
Repurchase Agreements | 2 to 3 years
Assets Sold under Agreements to Repurchase [Line Items]
Principal	0	0
Repurchase Agreements | Greater than 3 years
Assets Sold under Agreements to Repurchase [Line Items]
Principal	$ 358,581	$ 362,215
Repurchase Agreements | Weighted Average Borrowing Rates
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	7.48%	7.51%
Repurchase Agreements | Weighted Average Borrowing Rates | 1 to 29 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	7.56%	7.35%
Repurchase Agreements | Weighted Average Borrowing Rates | 30 to 59 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.71%	6.68%
Repurchase Agreements | Weighted Average Borrowing Rates | 60 to 89 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	7.21%	7.17%
Repurchase Agreements | Weighted Average Borrowing Rates | 90 to 119 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.29%	7.46%
Repurchase Agreements | Weighted Average Borrowing Rates | 120 to 180 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.89%	7.09%
Repurchase Agreements | Weighted Average Borrowing Rates | 180 days to 1 year
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	9.50%	7.06%
Repurchase Agreements | Weighted Average Borrowing Rates | 1 to 2 years
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	8.33%	9.36%
Repurchase Agreements | Weighted Average Borrowing Rates | Greater than 3 years
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	5.08%	5.11%
Repurchase Agreements | Minimum | 1 to 29 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.20%	6.30%
Repurchase Agreements | Minimum | 30 to 59 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	5.44%	5.58%
Repurchase Agreements | Minimum | 60 to 89 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	5.84%	5.93%
Repurchase Agreements | Minimum | 90 to 119 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.29%	6.59%
Repurchase Agreements | Minimum | 120 to 180 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.35%	6.72%
Repurchase Agreements | Minimum | 180 days to 1 year
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.63%	6.66%
Repurchase Agreements | Minimum | 1 to 2 years
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	8.33%	8.36%
Repurchase Agreements | Minimum | Greater than 3 years
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	5.08%	5.10%
Repurchase Agreements | Maximum | 1 to 29 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	8.18%	8.22%
Repurchase Agreements | Maximum | 30 to 59 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	7.82%	7.87%
Repurchase Agreements | Maximum | 60 to 89 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	7.58%	7.85%
Repurchase Agreements | Maximum | 90 to 119 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	6.29%	7.80%
Repurchase Agreements | Maximum | 120 to 180 days
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	7.65%	7.80%
Repurchase Agreements | Maximum | 180 days to 1 year
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	12.50%	7.39%
Repurchase Agreements | Maximum | 1 to 2 years
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	8.33%	12.50%
Repurchase Agreements | Maximum | Greater than 3 years
Assets Sold under Agreements to Repurchase [Line Items]
Borrowing rates (as a percent)	5.08%	7.15%