CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income		$ 105,334	$ 72,968	$ 71,392
Other Comprehensive (Loss) Income, Before Tax:
Net change in unrealized (losses) gains on equity securities	[1]	(6,794)	(1,275)	(2,899)
Net (gains) losses on debt securities available-for-sale reclassified into net income	[2]	0	(3,000)	0
Adjustment to funded status of employee benefit plans		6,297	(1,992)	6,974
Other Comprehensive (Loss) Income, Before Tax		(497)	(6,267)	4,075
Income tax benefit (expense) related to items of other comprehensive income		106	1,624	(1,402)
Other Comprehensive (Loss) Income, After Tax		(391)	(4,643)	2,673
Comprehensive Income		$ 104,943	$ 68,325	$ 74,065

[1] Due to the adoption of ASU No. 2016-01, net unrealized gains on marketable equity securities were reclassified from accumulated other comprehensive income to retained earnings during the three months ended March 31, 2018. The prior period data was not restated; as such, the change in unrealized gains on marketable securities is combined with the change in net unrealized gains on debt securities for the prior periods ended December 31, 2017 and 2016.

[2] Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income/(loss) and have affected certain lines in the Consolidated Statements of Net Income as follows: the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.