Other Comprehensive Income (Components of OCI) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Unrealized gains and losses on available for sale debt securities:
Net unrealized (losses) gains arising during the period	$ (10,765)	$ (578)	$ (19,630)	$ 20,733
Reclassification adjustment for gains included in net income	0	0	(230)	0
Total	(10,765)	(578)	(19,860)	20,733
Unrealized gains (losses) on derivatives (cash flow hedges)	2,382	1,186	6,959	(8,242)
Amortization related to post-retirement obligations	(138)	115	(435)	322
Total other comprehensive (loss) income	(8,521)	723	(13,336)	12,813
Unrealized gains and losses on available for sale debt securities:
Net unrealized (losses) gains arising during the period	2,775	150	5,061	(5,345)
Reclassification adjustment for gains included in net income	0	0	59	0
Total	2,775	150	5,120	(5,345)
Unrealized gains (losses) on derivatives (cash flow hedges)	(614)	(306)	(1,794)	2,125
Amortization related to post-retirement obligations	35	(30)	112	(83)
Total other comprehensive (loss) income	2,196	(186)	3,438	(3,303)
Unrealized gains and losses on available for sale debt securities:
Net unrealized (losses) gains arising during the period	(7,990)	(428)	(14,569)	15,388
Reclassification adjustment for gains included in net income	0	0	(171)	0
Total	(7,990)	(428)	(14,740)	15,388
Unrealized gains (losses) on derivatives (cash flow hedges)	1,768	880	5,165	(6,117)
Amortization related to post-retirement obligations	(103)	85	(323)	239
Total other comprehensive (loss) income	$ (6,325)	$ 537	$ (9,898)	$ 9,510