Accumulated Other Comprehensive Income (Loss) - AOCI Components Pre Post & Tax Effect (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
Other Comprehensive Income (Loss), Before Tax:
Net Unrealized Gains (Losses) Arising During the Period	$ (111,338)			$ (10,263)			$ (523,365)	$ (75,360)
(Gain) Loss on Sale				(83)				(3,758)
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	3,037			87			3,100	593
Net Unrealized Gains (Losses) on Investment Securities	(108,301)			(10,259)			(520,265)	(78,525)
Amortization of Net Actuarial Losses (Gains)	542			662			1,626	1,985
Amortization of Prior Service Credit	(61)			(62)			(184)	(185)
Defined Benefit Plans, Net	481			600			1,442	1,800
Other Comprehensive Income (Loss)	(107,820)			(9,659)			(518,823)	(76,725)
Other Comprehensive Income (Loss), Tax Effect:
Net Unrealized Gains (Losses) Arising During the Period	(29,506)			(2,719)			(138,715)	(19,954)
(Gain) Loss on Sale				(22)				(1,014)
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	805			23			821	157
Net Unrealized Gains (Losses) on Investment Securities	(28,701)			(2,718)			(137,894)	(20,811)
Amortization of Net Actuarial Losses (Gains)	143			175			431	525
Amortization of Prior Service Credit	(16)			(16)			(48)	(49)
Defined Benefit Plans, Net	127			159			383	476
Other Comprehensive Income (Loss)	(28,574)			(2,559)			(137,511)	(20,335)
Other Comprehensive Loss, Net of Tax:
Net Unrealized Gains (Losses) Arising During the Period	(81,832)			(7,544)			(384,650)	(55,406)
(Gain) Loss on Sale				(61)				(2,744)
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	2,232			64			2,279	436
Net Unrealized Gains (Losses) on Investment Securities	(79,600)			(7,541)			(382,371)	(57,714)
Amortization of Net Actuarial Losses (Gains)	399			487			1,195	1,460
Amortization of Prior Service Credit	(45)			(46)			(136)	(136)
Defined Benefit Plans, Net	354			441			1,059	1,324
Total Other Comprehensive Loss	$ (79,246)	$ (122,295)	$ (179,771)	$ (7,100)	$ 319	$ (49,609)	$ (381,312)	$ (56,390)