Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]
BALANCE, Shares at Dec. 31, 2013		17,611,000
BALANCE at Dec. 31, 2013	$ 476,887	$ 176	$ 269,884	$ 202,930	$ 3,897	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	50,386			50,386
Other comprehensive loss, net of tax	(37,843)				(37,843)
Common stock dividends paid	(2,681)			(2,681)
Stock options exercised, Shares		13,000
Stock options exercised	419	$ 0	419
Excess tax benefit from share-based compensation	756		756
Conversion of restricted stock units, Shares		58,000
Conversion of restricted stock units	(1,019)	$ (1)	(1,020)
Share-based compensation	7,188		7,188
BALANCE, Shares at Dec. 31, 2014		17,682,000
BALANCE at Dec. 31, 2014	494,093	$ 177	277,227	250,635	(33,946)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,863			9,863
Other comprehensive loss, net of tax	(32,042)				(32,042)
Common stock dividends paid	(2,559)			(2,559)
Stock options exercised, Shares		8,000
Stock options exercised	258		258
Tax effect from share-based compensation	134		134
Conversion of restricted stock units, Shares		56,000
Conversion of restricted stock units	(577)	$ 0	(577)
Share-based compensation	6,579		6,579
Repurchase of common stock, Shares						1,382,000
Sales of common stock	$ 74,972					$ 74,972
BALANCE, Shares at Dec. 31, 2015	16,364,299	16,364,000
BALANCE at Dec. 31, 2015	$ 400,777	$ 177	283,621	257,939	(65,988)	(74,972)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	10,101			10,101
Other comprehensive loss, net of tax	(10,273)				(10,273)
Common stock dividends paid	(2,497)			(2,497)
Stock options exercised, Shares		6,000
Stock options exercised	245		245
Excess tax benefit from share-based compensation	(145)		(145)
Conversion of restricted stock units, Shares		66,000
Conversion of restricted stock units	157	$ (1)	156
Share-based compensation	5,545		5,545
Repurchase of common stock, Shares		9,000
Sales of common stock	$ 500					500
BALANCE, Shares at Dec. 31, 2016	16,445,363	16,445,000
BALANCE at Dec. 31, 2016	$ 404,410	$ 178	$ 289,422	$ 265,543	$ (76,261)	$ (74,472)