CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Company Shares Held by SERP [Member]	Retained Earnings [Member]	Non-Controlling Interest [Member]	Total
Balance at Dec. 31, 2013	$ 4,572	$ 134,730	$ (4,894)	$ (2,786)	$ 442,054	$ 3,635	$ 577,311
Balance (in shares) at Dec. 31, 2013	22,859
Net income					34,458	(252)	34,206
Quarterly dividends		8			(9,175)		(9,167)
Other comprehensive loss			(8,021)			565	(7,456)
Change in ownership percent of subsidiary						(1,345)	(1,345)
Capital contributed by minority shareholder						1,583	1,583
Stock-based compensation	$ 1	1,199					1,200
Stock-based compensation (in shares)	5
Exercise of stock options and RSU vesting, including tax benefit	$ 13	855					868
Exercise of stock options and RSU vesting, including tax benefit (in shares)	66
Withholding tax on vested RSUs		(953)					(953)
Sale of Company stock held by SERP, net		48		(143)			(95)
Balance at Dec. 31, 2014	$ 4,586	135,887	(12,915)	(2,929)	467,337	4,186	596,152
Balance (in shares) at Dec. 31, 2014	22,930
Net income					32,797	(831)	31,966
Quarterly dividends		8			(9,201)		(9,193)
Other comprehensive loss			(10,649)			(772)	(11,421)
Change in ownership percent of subsidiary						(663)	(663)
Stock-based compensation	$ 1	1,249					1,250
Stock-based compensation (in shares)	4
Exercise of stock options and RSU vesting, including tax benefit	$ 11	406					417
Exercise of stock options and RSU vesting, including tax benefit (in shares)	54
Withholding tax on vested RSUs		(600)					(600)
Sale of Company stock held by SERP, net		933		1,151			2,084
Other						(134)	(134)
Balance at Dec. 31, 2015	$ 4,598	137,883	(23,564)	(1,778)	490,933	1,786	$ 609,858
Balance (in shares) at Dec. 31, 2015	22,988						22,988
Net income					55,159	(171)	$ 54,988
Quarterly dividends		9			(9,226)		(9,217)
Other comprehensive loss			(7,998)			34	(7,964)
Change in ownership percent of subsidiary						(1,322)	(1,322)
Stock-based compensation	$ 1	2,935					2,936
Stock-based compensation (in shares)	5
Exercise of stock options and RSU vesting, including tax benefit	$ 10	(10)					0
Exercise of stock options and RSU vesting, including tax benefit (in shares)	53
Withholding tax on vested RSUs		(1,024)					(1,024)
Sale of Company stock held by SERP, net		27		(180)			(153)
Other						684	684
Balance at Dec. 31, 2016	$ 4,609	139,970	$ (31,562)	$ (1,958)	536,771	$ 1,011	$ 648,841
Balance (in shares) at Dec. 31, 2016	23,046						23,046
Cumulative effect of adopting ASU No. 2016-09		$ 150			$ (95)		$ 55