CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Company Shares Held by SERP [Member]	Retained Earnings [Member]	Non-Controlling Interest [Member]	Total
Balance at Dec. 31, 2011	$ 4,542	$ 132,744	$ 841	$ (2,487)	$ 395,052	$ 606	$ 531,298
Balance (in shares) at Dec. 31, 2011	22,711
Net income					40,828	161	40,989
Dividends		16			(22,806)		(22,790)
Other comprehensive loss			(339)			15	(324)
Change in ownership percentage of subsidiary						862	862
Stock-based compensation	1	1,284					1,285
Stock-based compensation (in shares)	6
Exercise of stock options and RSU vesting, including tax benefit	17	604					621
Exercise of stock options and RSU vesting, including tax benefit (in shares)	82
Withholding tax on vested RSUs		(834)					(834)
Sale/Purchase of Company stock held by SERP, net		(5)		(368)			(373)
Balance at Dec. 31, 2012	4,560	133,809	502	(2,855)	413,074	1,644	550,734
Balance (in shares) at Dec. 31, 2012	22,799
Net income					39,042	172	39,214
Dividends		6			(6,862)		(6,856)
Other comprehensive loss			(5,396)			236	(5,160)
Change in ownership percentage of subsidiary						(802)	(802)
Capital Contributed By Minority Shareholder						2,385	2,385
Stock-based compensation	1	1,460					1,461
Stock-based compensation (in shares)	6
Exercise of stock options and RSU vesting, including tax benefit	11	93					104
Exercise of stock options and RSU vesting, including tax benefit (in shares)	54
Withholding tax on vested RSUs		(782)					(782)
Sale/Purchase of Company stock held by SERP, net		144		69			213
Balance at Dec. 31, 2013	4,572	134,730	(4,894)	(2,786)	445,254	3,635	580,511
Balance (in shares) at Dec. 31, 2013	22,859						22,859
Net income					34,458	(252)	34,206
Dividends		8			(9,175)		(9,167)
Other comprehensive loss			(8,021)			565	(7,456)
Change in ownership percentage 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/Purchase of Company stock held by SERP, net		48		(143)			(95)
Balance at Dec. 31, 2014	$ 4,586	$ 135,887	$ (12,915)	$ (2,929)	$ 470,537	$ 4,186	$ 599,352
Balance (in shares) at Dec. 31, 2014	22,930						22,930