Derivative Instruments and Hedging Activities - Derivative Instruments, Gain (Loss) in Statement of Financial Performance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ 46,327	$ (84,093)	$ 62,462	$ (181,289)
TBAs \| Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(4,787)	(10,757)	(46,836)	18,721
Futures \| Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	44,438	(25,152)	81,781	(54,915)
Options on futures \| Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	0	(105)	(159)	(124)
Interest rate swap agreements \| Payers \| Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	60,435	(89,808)	110,451	(296,989)
Interest rate swap agreements \| Receivers \| Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(49,901)	36,858	(81,178)	145,251
TBAs (pipeline) \| Income Statement Location [Axis]: us-gaap:GainLossOnSalesOfLoansNet
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(231)	(82)	373	(82)
Interest rate lock commitments \| Income Statement Location [Axis]: us-gaap:GainLossOnSalesOfLoansNet
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(120)	171	(230)	483
Forward mortgage loan sale commitments \| Income Statement Location [Axis]: us-gaap:GainLossOnSalesOfLoansNet
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	0	25	0	(143)
Inverse interest-only securities \| Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ (3,507)	$ 4,757	$ (1,740)	$ 6,509