Consolidated Statements of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income Loss	Treasury Stock
Balance at Dec. 31, 2008	$ 342,707	$ 544	$ 45,806	$ 605,001	$ (176,133)	$ (132,511)
Comprehensive income
Net income	123,442			123,442
Foreign currency translation adjustments					11,941
Change in benefit plans' net funded status, net of taxes of $27,164, $9,905 and $22,672 for the period ended 31 December 2009, 2010 and 2011 respectively					44,307
Other comprehensive income (loss)	56,248				56,248
Comprehensive income (loss)	179,690
Cash dividends declared ($0.36 per share)	(16,678)			(16,678)
Share-based compensation expense	3,502		3,502
Delivery of treasury shares
RSUs	(203)		(1,483)			1,280
401 (k) plans	1,522		(995)			2,517
Director compensation	164		(84)			248
Balance at Dec. 31, 2009	510,704	544	46,746	711,765	(119,885)	(128,466)
Comprehensive income
Net income	54,434			54,434
Foreign currency translation adjustments					(17,227)
Change in benefit plans' net funded status, net of taxes of $27,164, $9,905 and $22,672 for the period ended 31 December 2009, 2010 and 2011 respectively					15,865
Other comprehensive income (loss)	(1,362)				(1,362)
Comprehensive income (loss)	53,072
Tax effect on employee stock options exercised	(50)		(50)
Cash dividends declared ($0.36 per share)	(16,746)			(16,746)
Share-based compensation expense	3,962		3,962
Delivery of treasury shares
RSUs	(490)		(2,152)			1,662
401 (k) plans	1,642		(318)			1,960
Director compensation	163		(16)			179
Employee stock options exercised - net	185		(27)			212
Balance at Dec. 31, 2010	552,442	544	48,145	749,453	(121,247)	(124,453)
Comprehensive income
Net income	42,694			42,694
Foreign currency translation adjustments					(10,160)
Deferred gains on cash flow hedges, net of tax					1,185
Change in benefit plans' net funded status, net of taxes of $27,164, $9,905 and $22,672 for the period ended 31 December 2009, 2010 and 2011 respectively					(36,519)
Other comprehensive income (loss)	(45,494)				(45,494)
Comprehensive income (loss)	(2,800)
Tax effect on employee stock options exercised	90		90
Cash dividends declared ($0.36 per share)	(16,322)			(16,322)
Share-based compensation expense	3,633		3,633
Repurchase of common shares	(48,904)					(48,904)
Delivery of treasury shares
RSUs			(215)			215
401 (k) plans	1,967		(141)			2,108
Director compensation	164		(13)			177
Employee stock options exercised - net	134		(22)			156
Balance at Dec. 31, 2011	$ 490,404	$ 544	$ 51,477	$ 775,825	$ (166,741)	$ (170,701)