Unaudited Condensed Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	Total	Total Stockholders' Equity	Common Stock Common Class A	Common Stock Common Class B	Capital in Excess of Par Value	Retained Earnings	Foreign Currency Translation Adjustment	Deferred Gain (Loss) on Available for Sale Securities	Deferred Gain (Loss) on Cash Flow Hedging	Pension and Postretirement Plan Adjustment
Balance, beginning of period at Dec. 31, 2012		$ 281,331	$ 6,771	$ 1,582	$ 24,612	$ 270,227	$ (574)	$ 292	$ (286)	$ (21,293)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		508	75		433
Purchase of treasury shares		(5,100)	(90)		(5,010)
Net income (loss)	4,422	4,422				4,422
Cash dividends		(2,102)				(2,102)
Current period other comprehensive income (loss)		843					479	244	120
Reclassification adjustment to net income		591							149	442
Balance, end of period at Mar. 31, 2013		280,493	6,756	1,582	20,035	272,547	(95)	536	(17)	(20,851)
Balance, beginning of period at Dec. 31, 2013		297,780	6,290	1,581	941	301,227	(803)	1,021	676	(13,153)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		417	19		398
Purchase of treasury shares		(4,986)	(91)		(1,339)	(3,556)
Net income (loss)	(1,524)	(1,524)				(1,524)
Cash dividends		(1,964)				(1,964)
Current period other comprehensive income (loss)		(518)					(174)	63	(407)
Reclassification adjustment to net income		338							180	158
Balance, end of period at Mar. 31, 2014		$ 289,543	$ 6,218	$ 1,581	$ 0	$ 294,183	$ (977)	$ 1,084	$ 449	$ (12,995)