Accumulated Other Comprehensive Income (Changes in AOCI by Component) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (384,615)	$ 97,109	$ 35,162	$ 182,195
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(170,224)	(22,022)	(583,072)	(102,777)
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	(4,005)	(2,370)	(10,934)	(6,701)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	(174,229)	(24,392)	(594,006)	(109,478)
Ending balance	(558,844)	72,717	(558,844)	72,717
Unrealized Gains and Losses on Available-for-Sale Debt Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(392,870)	81,833	23,134	163,174
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(170,224)	(22,022)	(583,072)	(102,777)
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	(2,086)	(465)	(5,242)	(1,051)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	(172,310)	(22,487)	(588,314)	(103,828)
Ending balance	(565,180)	59,346	(565,180)	59,346
Unrealized Gains and Losses on Pension Plan Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(4,611)	(5,603)	(4,812)	(5,833)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0	0
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	100	114	301	344
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	100	114	301	344
Ending balance	(4,511)	(5,489)	(4,511)	(5,489)
Unrealized gains and losses on cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	12,866	20,879	16,840	24,854
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0	0
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	(2,019)	(2,019)	(5,993)	(5,994)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	(2,019)	(2,019)	(5,993)	(5,994)
Ending balance	$ 10,847	$ 18,860	$ 10,847	$ 18,860