Accumulated Other Comprehensive Income (Loss) - AOCI Reclass to IS (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	$ (56,175)		$ (57,769)		$ (121,263)	$ (117,693)
Provision for Income Tax	(15,006)		(17,759)		(30,937)	(33,365)
Net Income (Loss)	46,061	$ 46,842	56,862	$ 54,834	92,903	111,696
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Net Income (Loss)	(5,082)		(350)		(10,247)	(752)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of Unrealized Gains(Losses) of Investment Securities Transferred from AFS to HTM
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Interest Income	(6,801)		3		(13,714)	(63)
Provision for Income Tax	1,803		(1)		3,635	16
Net Income (Loss)	(4,998)		2		(10,079)	(47)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	62		61		123	123
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	(177)		(542)		(352)	(1,084)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	(115)		(481)		(229)	(961)
Provision for Income Tax	31		129		61	256
Net Income (Loss)	$ (84)		$ (352)		$ (168)	$ (705)