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Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021				$ 115,099
Amounts reclassified from AOCI, HTM related		$ 0	$ (2)	1	$ (4)
Amount reclassified into net income: Net actuarial loss, Net		330	548	659	1,095
Net current period OCI		(206,575)	34,771	(451,469)	(50,815)
Net current period OCI, defined benefit pension and post-retirement plans		330	548	659	1,095
Ending Balance, June 30, 2022		(336,370)		(336,370)
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021				185,170
OCI before reclassifications				(382,941)
Amounts reclassified from AOCI, All Other				26,987
Net current period OCI				(355,954)
Ending Balance, June 30, 2022		(170,784)		(170,784)
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021				180,880
OCI before reclassifications				(508,798)
Amounts reclassified from AOCI				56,670
Net current period OCI				(452,128)
Ending Balance, June 30, 2022		(271,248)		(271,248)
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021	[1]			(4,287)
OCI before reclassifications	[1]			(125,857)
Amounts reclassified from AOCI, Credit loss related	[1]			29,682
Net current period OCI	[1]			(96,175)
Ending Balance, June 30, 2022	[1]	(100,462)		(100,462)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021				(3)
OCI before reclassifications				0
Amounts reclassified from AOCI, HTM related				1
Net current period OCI				1
Ending Balance, June 30, 2022		(2)		(2)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021				(65,781)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans				0
Amount reclassified into net income: Net actuarial loss, Net				659
Ending Balance, June 30, 2022		(65,122)		(65,122)
Accumulated other comprehensive income (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2021				115,099
OCI before reclassifications				(508,798)
Amounts reclassified from AOCI				57,329
Net current period OCI		(206,575)	$ 34,771	(451,469)	$ (50,815)
Ending Balance, June 30, 2022		$ (336,370)		$ (336,370)
[1] 1Represents change in unrealized loss on securities with credit loss recognized in earnings.

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