CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2018	$ 810,269	$ 500	$ 619,850	$ 410,641	$ (72,861)	$ (147,861)
Beginning Balance (Shares) at Dec. 31, 2018		44,690				5,296
Net income	18,085			18,085
Common stock dividends declared	(12,339)			(12,339)
Other comprehensive (loss) income	5,105				5,105
Exercise of stock options	1,690	$ 1	1,689
Exercise of stock options (Shares)		66
Purchase of treasury stock	(1,057)					$ (1,057)
Purchase of treasury stock (Shares)		(29)				29
Restricted stock grants, net		$ 2	(2)
Restricted stock grants, net (Shares)		248
Share-based compensation	3,404		3,404
Ending Balance at Mar. 31, 2019	825,157	$ 503	624,941	416,387	(67,756)	$ (148,918)
Ending Balance (Shares) at Mar. 31, 2019		44,975				5,325
Beginning Balance at Dec. 31, 2019	841,362	$ 504	638,083	445,285	(65,093)	$ (177,417)
Beginning Balance (Shares) at Dec. 31, 2019		44,152				6,229
Net income	8,301			8,301
Common stock dividends declared	(13,442)			(13,442)
Other comprehensive (loss) income	(14,385)				(14,385)
Exercise of stock options	$ 752		752
Exercise of stock options (Shares)	24	24
Purchase of treasury stock	$ (900)					$ (900)
Purchase of treasury stock (Shares)		(22)				22
Restricted stock grants, net		$ 2	(2)
Restricted stock grants, net (Shares)		225
Share-based compensation	2,682		2,682
Ending Balance at Mar. 31, 2020	$ 824,370	$ 506	$ 641,515	$ 440,144	$ (79,478)	$ (178,317)
Ending Balance (Shares) at Mar. 31, 2020		44,379				6,251