Accumulated Other Comprehensive Income (Loss) - Changes in components of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accumulated Other Comprehensive Loss
Balance	$ 5,890,415	$ 5,533,098
Net comprehensive loss	230,254	(40,458)
Balance	8,624,361	5,547,009
Benefit Plans
Accumulated Other Comprehensive Loss
Balance	578	627
Balance	578	627
Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Loss
Balance	(607,499)	(583,163)
Other comprehensive income (loss) before reclassifications	56,586	(40,458)
Amounts reclassified from accumulated other comprehensive loss	173,668
Net comprehensive loss	230,254	(40,458)
Balance	(377,245)	(623,621)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss
Balance	(606,921)	(582,536)
Other comprehensive income (loss) before reclassifications	56,586	(40,458)
Amounts reclassified from accumulated other comprehensive loss	173,668
Net comprehensive loss	230,254	(40,458)
Balance	$ (376,667)	$ (622,994)