Accumulated Other Comprehensive Income (Loss) (AOCI Components Pre Post & Tax Effect) (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Comprehensive Income (Loss), Before Tax:
Net Unrealized Gains (Losses) Arising During the Period	$ (13,057)	$ 7,580
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	659	504
Net Unrealized Gains (Losses) on Investment Securities	(12,398)	8,084
Amortization of Net Actuarial Losses (Gains)	436	323
Amortization of Prior Service Credit	(142)	(81)
Defined Benefit Plans, Net	294	242
Other Comprehensive Income (Loss)	(12,104)	8,326
Other Comprehensive Income (Loss), Tax Effect:
Net Unrealized Gains (Losses) Arising During the Period	(3,452)	2,991
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	175	199
Net Unrealized Gains (Losses) on Investment Securities	(3,277)	3,190
Amortization of Net Actuarial Losses (Gains)	116	128
Amortization of Prior Service Credit	(38)	(32)
Defined Benefit Plans, Net	78	96
Other Comprehensive Income (Loss)	(3,199)	3,286
Other Comprehensive Income (Loss), Net of Tax:
Net Unrealized Gains (Losses) Arising During the Period	(9,605)	4,589
Amortization of Unrealized Holding (Gains) Losses on HTM Securities	484	305
Net Unrealized Gains (Losses) on Investment Securities	(9,121)	4,894
Amortization of Net Actuarial Losses (Gains)	320	195
Amortization of Prior Service Credit	(104)	(49)
Defined Benefit Plans, Net	216	146
Total Other Comprehensive Income (Loss)	$ (8,905)	$ 5,040