Consolidated Statement of Shareholders' Equity - 3 months ended Mar. 31, 2019 - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Restricted Shares	Restricted Shares Common Stock	Restricted Shares Treasury Stock
Balance, December 31, 2018 at Dec. 31, 2018	$ 520,140	$ 386,814	$ 160,346	$ (12,933)	$ (14,087)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14,369		14,369
Other comprehensive income, net of tax	0
Other comprehensive income, net of tax	5,436			5,436
Cash dividends declared	(5,868)		(5,868)
Reissuance of treasury stock for deferred compensation plan for Boards of Directors						$ 0	$ (2,761)	$ 2,761
Reissuance of treasury stock for deferred compensation plan for Boards of Directors	2				2
Repurchase of treasury stock in connection with employee incentive plan and under compensation plan for Boards of Directors	(450)				(450)
Common shares issued under dividend reinvestment plan	181	181
Common shares issued under compensation plan for Boards of Directors	158	40			118
Share-based Compensation	1,153	1,153
Balance, March 31, 2019 at Mar. 31, 2019	$ 535,121	$ 385,427	$ 168,847	$ (7,497)	$ (11,656)