Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Total Stockholders' Equity	Common Stock Shares Outstanding Class A	Common Stock Shares Outstanding 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	Noncontrolling Interest
Balance, beginning of period at Dec. 31, 2011	$ 577,092	$ 576,210	$ 6,778	$ 1,596	$ 22,786	$ 619,614	$ 13,210	$ 27	$ 2,597	$ (90,398)	$ 882
Stockholders’ equity
Stock-based compensation	4,983	4,983	30		4,953
Purchase of treasury shares	(3,178)	(3,178)	(51)		(3,127)
Conversion of Class B to Class A shares	0	0	14	(14)
Net income (loss)	108,698	108,698				108,698
Cash dividends	(45,130)	(45,130)				(45,130)
Stock dividend	(370,614)	(369,732)				(412,955)	(13,929)		(7,784)	64,936	(882)
Current period other comprehensive income (loss)	6,352	6,352					145	265	7,658	(1,716)	0
Reclassification adjustment to net income	3,128	3,128							(2,757)	5,885
Balance, end of period at Dec. 31, 2012	281,331	281,331	6,771	1,582	24,612	270,227	(574)	292	(286)	(21,293)	0
Stockholders’ equity
Stock-based compensation	1,807	1,807	83		1,724
Purchase of treasury shares	(31,306)	(31,306)	(565)		(26,336)	(4,405)
Conversion of Class B to Class A shares	0	0	1	(1)
Net income (loss)	44,450	44,450				44,450
Cash dividends	(8,104)	(8,104)				(8,104)
Current period other comprehensive income (loss)	9,332	9,332				0	(229)	729	810	8,022	0
Current period curtailment gain	(983)	(983)					0	0	0	(983)
Reclassification adjustment to net income	1,253	1,253							152	1,101
Balance, end of period at Dec. 31, 2013	297,780	297,780	6,290	1,581	0	302,168	(803)	1,021	676	(13,153)	0
Stockholders’ equity
Stock-based compensation	2,572	2,572	28		2,544
Purchase of treasury shares	(35,075)	(35,075)	(664)		(2,544)	(31,867)
Conversion of Class B to Class A shares	0	0	8	(8)
Net income (loss)	(38,118)	(38,118)				(38,118)
Cash dividends	(7,755)	(7,755)				(7,755)
Current period other comprehensive income (loss)	(9,455)	(9,455)					(1,896)	442	(1,518)	(6,483)
Reclassification adjustment to net income	1,525	1,525							898	627
Balance, end of period at Dec. 31, 2014	$ 211,474	$ 211,474	$ 5,662	$ 1,573	$ 0	$ 224,428	$ (2,699)	$ 1,463	$ 56	$ (19,009)	$ 0