Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (124,972)
Labor and Related Expense	(487,063)	$ (482,676)	$ (428,976)
Reclassification from OCI due to change in accounting principle	0	(84)	0
Interest income	895	(572)	(2,665)
Total other comprehensive income (loss)	91,789	(62,214)	(8,079)
Ending Balance	(33,183)	(124,972)
Investment Securities Available For Sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(75,643)	(38,453)	(20,079)
Other comprehensive income (loss) before reclassifications	111,592	(39,891)	(27,040)
Investment securities losses (gains), net	(5,957)	1,985
Labor and Related Expense	0	0	0
Other Expenses	0	0	0
Reclassification from OCI due to change in accounting principle		(84)
Adjustment for adoption of ASU 2018-02		(8,419)
Interest income	895	(572)	(2,665)
Other Comprehensive Income (Loss), Tax	(26,898)	9,791	11,331
Total other comprehensive income (loss)	79,631	(37,189)	(18,374)
Ending Balance	3,989	(75,643)	(38,453)
Defined Benefit Pension and Postretirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(49,330)	(24,305)	(34,600)
Other comprehensive income (loss) before reclassifications	16,296	(28,612)	14,273
Investment securities losses (gains), net	0	0
Labor and Related Expense	(148)	(148)	(148)
Other Expenses	476	2,203	2,282
Reclassification from OCI due to change in accounting principle		0
Adjustment for adoption of ASU 2018-02		(5,235)
Interest income	0	0	0
Other Comprehensive Income (Loss), Tax	(4,465)	6,767	(6,112)
Total other comprehensive income (loss)	12,158	(25,025)	10,295
Ending Balance	(37,172)	(49,330)	(24,305)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(124,972)	(62,758)	(54,679)
Other comprehensive income (loss) before reclassifications	127,887	(68,503)	(12,767)
Investment securities losses (gains), net	(5,957)	1,985
Labor and Related Expense	(148)	(148)	(148)
Other Expenses	476	2,203	2,282
Reclassification from OCI due to change in accounting principle		(84)
Adjustment for adoption of ASU 2018-02		(13,654)
Interest income	895	(572)	(2,665)
Other Comprehensive Income (Loss), Tax	(31,363)	16,558	5,219
Total other comprehensive income (loss)	91,789	(62,214)	(8,079)
Ending Balance	$ (33,183)	$ (124,972)	$ (62,758)

Accumulated Other Comprehensive Income (Loss) [Roll Forward]

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Amortization of Net Unrealized Gain on Available-for-Sale Securities Transfered to Held-to-maturity Securities

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Reporting Comprehensive Income(2018-02)

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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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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of expense for salary, wage, profit sharing; incentive and equity-based compensation; and other employee benefit.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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