Consolidated Statements of 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	Noncontrolling Interest
Balance, beginning of period at Dec. 31, 2010	$ 448,215	$ 447,413	$ 6,737	$ 1,596	$ 22,668	$ 475,338	$ 28,152	$ 0	$ (8,953)	$ (78,125)	$ 802
Capital in Excess of Par Value
Stock-based compensation	2,222	2,222	65		2,157
Purchase of treasury shares	(2,063)	(2,063)	(24)		(2,039)
Retained Earnings
Net income attributable to stockholders	162,071	162,071				162,071
Cash dividends	(17,795)	(17,795)				(17,795)
Accumulated Other Comprehensive Income (Loss)
Current period other comprehensive income (loss)	(31,497)	(31,497)					(14,942)	27	2,395	(18,977)
Current period curtailment gain	0
Reclassification adjustment to net income	(15,859)	(15,859)							(9,155)	(6,704)
Noncontrolling Interest
Net income attributable to noncontrolling interest	80										80
Balance, end 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
Capital in Excess of Par Value
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		14	(14)
Retained Earnings
Net income attributable to stockholders	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)
Accumulated Other Comprehensive Income (Loss)
Current period other comprehensive income (loss)	6,352	6,352					145	265	7,658	(1,716)
Current period curtailment gain	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
Capital in Excess of Par Value
Stock-based compensation	1,807	1,807	83		1,724
Purchase of treasury shares	(31,306)	(31,306)	(565)		(25,395)	(5,346)
Conversion of Class B to Class A shares	0	0	1	(1)
Retained Earnings
Net income attributable to stockholders	44,450	44,450				44,450
Cash dividends	(8,104)	(8,104)				(8,104)
Accumulated Other Comprehensive Income (Loss)
Current period other comprehensive income (loss)	9,332	9,332					(229)	729	810	8,022
Current period curtailment gain	(983)	(983)								(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	$ 941	$ 301,227	$ (803)	$ 1,021	$ 676	$ (13,153)	$ 0