Accumulated Other Comprehensive Income (Loss) (AOCI Components Pre Post & Tax Effect) (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Other Comprehensive Income (Loss), Before Tax:
Net Unrealized Gains (Losses) Arising During the Period	$ 56,556	$ 8,952
(Gain) Loss on sale, before tax	77	(64)
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	65	396
Net Unrealized Gains (Losses) on Investment Securities	56,544	9,412
Amortization of Net Actuarial Losses (Gains)	570	406
Amortization of Prior Service Credit	(61)	(72)
Defined Benefit Plans, Net	509	334
Other Comprehensive Income (Loss)	57,053	9,746
Other Comprehensive Income (Loss), Tax Effect:
Net Unrealized Gains (Losses) Arising During the Period	14,989	2,371
(Gain) Loss on sale, Tax Effect	21	(17)
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	17	105
Net Unrealized Gains (Losses) on Investment Securities	14,985	2,493
Amortization of Net Actuarial Losses (Gains)	152	107
Amortization of Prior Service Credit	(17)	(19)
Defined Benefit Plans, Net	135	88
Other Comprehensive Income (Loss)	15,120	2,581
Other Comprehensive Income (Loss), Net of Tax:
Net Unrealized Gains (Losses) Arising During the Period	41,567	6,581
(Gain) Loss on sale, Net of Tax	56	(47)
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	48	291
Net Unrealized Gains (Losses) on Investment Securities	41,559	6,919
Amortization of Net Actuarial Losses (Gains)	418	299
Amortization of Prior Service Credit	(44)	(53)
Defined Benefit Plans, Net	374	246
Total Other Comprehensive Income (Loss)	$ 41,933	$ 7,165