CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Non-controlling Interests [Member]	Total
Balance at Dec. 31, 2008	$ 2,883	$ 312,972	$ 863,601	$ (31,634)	$ (436,238)	$ 23,247	$ 734,831
Comprehensive Income (loss):
Net income (loss)			(23,796)			2,892	(20,904)
Currency translation adjustment				23,479		873	24,352
Unamortized gains (losses) and prior service cost				12,789			12,789
Cash flow hedge:
Net derivative gains (losses) arising during the year				(1,548)			(1,548)
Reclassification adjustment				(107)			(107)
Total comprehensive income (loss)			(23,796)	34,827		3,765	14,796
Dividends declared			(3,743)				(3,743)
Dividends to non-controlling interests						(3,430)	(3,430)
Employee benefit transactions	5	322					327
Income tax benefit arising from employee stock option plans		56					56
Stock-based compensation		4,906					4,906
Balance at Dec. 31, 2009	2,888	318,256	836,062	3,193	(436,238)	23,582	747,743
Comprehensive Income (loss):
Net income (loss)			66,869			3,017	69,886
Currency translation adjustment				(9,195)		1,022	(8,173)
Unamortized gains (losses) and prior service cost				347			347
Cash flow hedge:
Net derivative gains (losses) arising during the year				2,020			2,020
Reclassification adjustment				(45)			(45)
Total comprehensive income (loss)			66,869	(6,783)		4,039	64,125
Dividends declared			(3,720)				(3,720)
Dividends to non-controlling interests						(449)	(449)
Employee benefit transactions	9	1,231					1,240
Income tax benefit arising from employee stock option plans		189					189
Stock-based compensation		3,559					3,559
Purchase of common stock for treasury					(29,992)		(29,992)
Balance at Dec. 31, 2010	2,897	323,235	899,211	(3,590)	(466,230)	27,172	782,695
Comprehensive Income (loss):
Net income (loss)			67,521			2,733	70,254
Sale of 50% Interest						(820)	(820)
Currency translation adjustment				(16,687)		(878)	(17,565)
Unamortized gains (losses) and prior service cost				(25,630)			(25,630)
Cash flow hedge:
Net derivative gains (losses) arising during the year				529			529
Reclassification adjustment				(47)			(47)
Total comprehensive income (loss)			67,521	(41,741)		1,035	26,815
Dividends declared			(3,602)				(3,602)
Dividends to non-controlling interests						(1,799)	(1,799)
Employee benefit transactions	16	5,895					5,911
Income tax benefit arising from employee stock option plans		172					172
Stock-based compensation		5,832					5,832
Purchase of common stock for treasury					(48,004)		(48,004)
Balance at Dec. 31, 2011	$ 2,913	$ 335,134	$ 963,130	$ (45,331)	$ (514,234)	$ 26,408	$ 768,020