Comprehensive Income - Components of Comprehensive Income-Gross and Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income, Gross	$ 102,566	$ 114,759
Unrealized holding gains (losses) during the period, Gross	(15,560)	65,925
Unrealized gains (losses) on securities with credit loss recognized in earnings, Gross	(3,132)	22,431
Amounts reclassified into net income: net realized (gains) losses on disposals and intent-to-sell AFS securities, Gross	(78)	6,104
Amounts reclassified into net income: Credit loss (benefit) expense, Gross	2,650	(9,529)
Total unrealized gains (losses) on investment securities, Gross	(16,120)	84,931
Amount reclassified into net income: Net actuarial (gain) loss, Gross	967	757
Total defined benefit pension and post-retirement plans, Gross	967	757
Other comprehensive income (loss), Gross	(15,153)	85,688
Comprehensive income (loss), Gross	87,413	200,447
Net income, Tax	20,048	22,185
Unrealized holding gains (losses) during the period, Tax	(3,267)	13,846
Unrealized gains (losses) on securities with credit loss recognized in earnings, Tax	(658)	4,710
Amounts reclassified into net income: net realized (gains) losses on disposals and intent-to-sell AFS securities, Tax	(17)	1,282
Amounts reclassified into net income: Credit loss (benefit) expense, Tax	557	(2,002)
Total unrealized gains (losses) on investment securities, Tax	(3,385)	17,836
Amount reclassified into net income: Net actuarial (gain) loss, Tax	203	159
Total defined benefit pension and post-retirement plans, Tax	203	159
Other comprehensive income (loss), Tax	(3,182)	17,995
Comprehensive income (loss), Tax	16,866	40,180
Net income	82,518	92,574
Unrealized holding gains (losses) during the period, Net	(12,293)	52,079
Unrealized gains (losses) on securities with credit loss recognized in earnings, Net	(2,474)	17,721
Amounts reclassified into net income: net realized (gains) losses on disposals and intent-to-sell AFS securities, Net	(61)	4,822
Amounts reclassified into net income: Credit loss (benefit) expense, Net	2,093	(7,527)
Total unrealized gains (losses) on investment securities	(12,735)	67,095
Amount reclassified into net income: Net actuarial (gain) loss, Net	764	598
Total defined benefit pension and post-retirement plans	764	598
Other comprehensive income (loss)	(11,971)	67,693
Comprehensive income (loss)	$ 70,547	$ 160,267