Accumulated Other Comprehensive Income (Loss) - AOCI Reclass to IS (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	$ (59,938)			$ (56,447)			$ (177,631)	$ (168,859)
Provision for Income Tax	(13,765)			(20,025)			(47,130)	(59,035)
Net Income	52,801	$ 56,862	$ 54,834	62,053	$ 67,533	$ 59,949	164,497	189,535
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Net Income	(2,586)			(444)			(3,338)	984
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	(3,037)			(87)			(3,100)	(593)
Provision for Income Tax	805			23			821	157
Net Income	(2,232)			(64)			(2,279)	(436)
Reclassification out of Accumulated Other Comprehensive Income | Sale of Investment Securities Available-for-Sale
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Sale of Investment Securities Available-for-Sale	0			83			0	3,758
Provision for Income Tax	0			(22)			0	(1,014)
Net Income	0			61			0	2,744
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	61			62			184	185
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	(542)			(662)			(1,626)	(1,985)
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	(481)			(600)			(1,442)	(1,800)
Provision for Income Tax	127			159			383	476
Net Income	$ (354)			$ (441)			$ (1,059)	$ (1,324)