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Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance December, | $ 220,186 |  |
Amount reclassified from AOCI, HTM | (9) | $ (19) | $ (46)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans | 17,093 | (1,197) | (10,898)
Amounts reclassified from AOCI,All other | (3,022) | 4,247 | 530
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax | 19,283 | 3,579 | (8,799)
Other comprehensive (loss) income | (105,087) | 138,436 | 159,706
Balance December, | 115,099 | 220,186 |
Accumulated Other-than-Temporary Impairment [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance December, | (2,546) | (71) |
Amounts reclassified into net income: Credit loss related | 5,418 | 3,984 |
Other comprehensive (loss) income | (1,741) | (2,475) |
Balance December, | (4,287) | (2,546) | (71)
Accumulated Net Unrealized Investment Gain (Loss) [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
OCI before reclassifications | (7,159) | (6,459) |
Accumulated Defined Benefit Plans Adjustment [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance, December 31, 2018 |  |  | (88,643)
Balance December, | (85,064) |  |
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans | 17,093 | 1,197 |
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax | 2,190 | 2,382 |
Balance December, | (65,781) | (85,064) |
Accumulated other comprehensive (loss) income [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance, December 31, 2018 |  |  | 81,750
Balance December, | 220,186 |  |
OCI before reclassifications | (109,664) | 127,842 |
Amount reclassified from AOCI | 4,577 | 10,594 |
Other comprehensive (loss) income | (105,087) | 138,436 | 159,706
Balance December, | 115,099 | 220,186 |
Held-to-maturity Securities [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance, December 31, 2018 |  |  | 25
Balance December, | 6 |  |
OCI before reclassifications | 0 | 0 |
Other comprehensive (loss) income | (9) | (19) |
Balance December, | (3) | 6 |
Available-for-sale Securities [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance, December 31, 2018 |  |  | 170,439
Balance December, | 307,790 |  |
OCI before reclassifications | (119,598) | 133,104 |
Amounts reclassified from AOCI,All other | (3,022) | 4,247 |
Other comprehensive (loss) income | (122,620) | 137,351 |
Balance December, | 185,170 | 307,790 |
Investments [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Balance, December 31, 2018 |  |  | $ 170,393
Balance December, | 305,250 |  |
OCI before reclassifications | (126,757) | 126,645 |
Amount reclassified from AOCI | 2,387 | 8,212 |
Other comprehensive (loss) income | (124,370) | 134,857 |
Balance December, | $ 180,880 | $ 305,250 |

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