Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Common Shares	Additional Paid-in Capital	Treasury Shares	Accumulated Other Comprehensive Loss	Retained Earnings	Noncontrolling Interest
Beginning Balance at Dec. 31, 2009	$ 406,276	$ 96	$ 175,477	$ (15,554)	$ (25,314)	$ 258,662	$ 12,909
Increase (Decrease) in Stockholders' Equity
Net income	64,881					64,662	219
Other comprehensive loss	(3,485)				(3,485)
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax	3,894		2,398	1,496
Dividends declared	(7,007)					(7,007)
Ending Balance at Dec. 31, 2010	464,559	96	177,875	(14,058)	(28,799)	316,317	13,128
Increase (Decrease) in Stockholders' Equity
Net income	96,825					95,106	1,719
Other comprehensive loss	(14,291)				(14,291)
Purchase of treasury shares	(3,039)			(3,039)
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax	3,688		1,588	2,100
Dividends declared	(8,900)					(8,900)
Ending Balance at Dec. 31, 2011	538,842	96	179,463	(14,997)	(43,090)	402,523	14,847
Increase (Decrease) in Stockholders' Equity
Net income	75,565					79,480	(3,915)
Other comprehensive loss	(2,289)				(2,289)
Proceeds received from minority investor	6,100						6,100
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax	4,602		2,164	2,438
Dividends declared	(11,375)					(11,375)
Ending Balance at Dec. 31, 2012	$ 611,445	$ 96	$ 181,627	$ (12,559)	$ (45,379)	$ 470,628	$ 17,032