Accumulated Other Comprehensive Income (Changes in AOCI by Component) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 35,162	$ 182,195
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(259,988)	(102,605)
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	(2,951)	(1,862)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	(262,939)	(104,467)
Ending balance	(227,777)	77,728
Unrealized Gains and Losses on Available-for-Sale Debt Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	23,134	163,174
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(259,988)	(102,605)
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	(1,076)	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	(261,064)	(102,605)
Ending balance	(237,930)	60,569
Unrealized Gains and Losses on Pension Plan Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(4,812)	(5,833)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	101	115
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	101	115
Ending balance	(4,711)	(5,718)
Unrealized gains and losses on cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	16,840	24,854
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Reclassification from Accumulated Other Comprehensive Income (Loss), Current Period, Net of Tax	(1,976)	(1,977)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	(1,976)	(1,977)
Ending balance	$ 14,864	$ 22,877

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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