CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total		Common Stock	Additional Paid-in Capital	Retained Earnings		Accumulated Other Comprehensive (Loss)/Income		Reclassifications Related to Funded Status of Pension	Reclassifications Related to Unrealized Gains on Available for Sale Securities	Treasury Stock
Beginning balance at Dec. 31, 2016	$ 841,956		$ 90,326	$ 213,098	$ 585,891		$ (13,784)				$ (33,575)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	72,968				72,968
Other comprehensive income (loss), net of tax	(4,643)						(4,643)
Cash dividends declared	(28,569)				(28,569)
Treasury stock issued	(689)				(2,183)						1,494
Recognition of restricted stock compensation expense	3,008			3,008
Ending balance at Dec. 31, 2017	884,031		90,326	216,106	628,107		(18,427)				(32,081)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	105,334				105,334
Other comprehensive income (loss), net of tax	(391)						(391)
Reclassification of tax effects from the Tax Act | ASU No. 2018-02	0	[1]			3,427	[1]	(3,427)	[1]	$ (3,660)	$ 233
Repurchase of warrant	(7,652)			(7,652)
Cash dividends declared	(34,539)				(34,539)
Treasury stock repurchased	(12,256)										(12,256)
Treasury stock issued	(657)				(1,372)						715
Recognition of restricted stock compensation expense	1,891			1,891
Ending balance at Dec. 31, 2018	935,761		90,326	210,345	701,819		(23,107)				(43,622)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	98,234				98,234
Other comprehensive income (loss), net of tax	11,437						11,437
Cash dividends declared	(37,360)				(37,360)
Common stock issuance cost	(176)			(176)
Common stock issued in acquisition	200,631		13,297	187,334
Treasury stock repurchased	(18,222)										(18,222)
Treasury stock issued	(915)				(1,777)						862
Recognition of restricted stock compensation expense	2,441			2,441
Ending balance at Dec. 31, 2019	$ 1,191,998		$ 103,623	$ 399,944	$ 761,083		$ (11,670)				$ (60,982)

[1] Reclassification of tax effects due to the adoption of ASU No. 2018-02, relating to $(3,660) relates to funded status of pension and $233 relates to net unrealized gains on available-for-sale securities.