Consolidated Statements of Equity (USD $) In Thousands, except Share data	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2009	$ 389	$ 242,563	$ 286,787	$ 18,602	$ 5,470	$ 553,811
Balance (in Shares) at Dec. 31, 2009	38,933,944
Net income			60,462		1,418	61,880
Issuance of common stock upon stock option exercises including tax benefit	1	2,302				2,303
Issuance of common stock upon stock option exercises including tax benefit (in Shares)	132,485					(132,485)
Restricted shares issued	2					2
Restricted shares issued (in Shares)	184,656
Issurance of shares pursuant to restricted stock units (in Shares)	32,156
Issuance of shares pursuant to deferred stock unit awards (in Shares)	9,231
Forfeitures of restricted shares (in Shares)	(46,457)
Equity-based compensation expense		6,713				6,713
Investment by non-controlling interests					2,578	2,578
Purchase of non-controlling interests						(398)
Distribution to non-controlling interests					(398)	(398)
Currency translation adjustment and derivative transactions, net				(489)	307	(182)
Balance at Dec. 31, 2010	392	251,578	347,249	18,113	9,375	626,707
Balance (in Shares) at Dec. 31, 2010	39,246,015
Net income			26,547		1,123	27,670
Issuance of common stock upon stock option exercises including tax benefit	1	3,610				3,611
Issuance of common stock upon stock option exercises including tax benefit (in Shares)	128,052					(128,052)
Restricted shares issued	2					2
Restricted shares issued (in Shares)	168,018
New shares issued	2	3,998				4,000
New shares issued (in Shares)	246,760
Issurance of shares pursuant to restricted stock units (in Shares)	9,934
Issuance of shares pursuant to deferred stock unit awards (in Shares)	20,640
Forfeitures of restricted shares (in Shares)	(140,448)
Shares repurchased and retired	(3)	(4,997)				(5,000)
Shares repurchased and retired (in Shares)	(326,596)
Equity-based compensation expense		6,491				6,491
Investment by non-controlling interests					546	546
Purchase of non-controlling interests						(1,661)
Distribution to non-controlling interests					(1,661)	(1,661)
Currency translation adjustment and derivative transactions, net				(12,251)	(1,126)	(13,377)
Balance at Dec. 31, 2011	394	260,680	373,796	5,862	8,257	648,989
Balance (in Shares) at Dec. 31, 2011	39,352,375
Net income			52,661		4,188	56,849
Issuance of common stock upon stock option exercises including tax benefit	1	1,175				1,176
Issuance of common stock upon stock option exercises including tax benefit (in Shares)	52,676					(52,676)
Restricted shares issued	2					2
Restricted shares issued (in Shares)	239,523
Issurance of shares pursuant to restricted stock units (in Shares)	15,177
Issuance of shares pursuant to deferred stock unit awards (in Shares)	34,132
Forfeitures of restricted shares (in Shares)	(36,325)
Shares repurchased and retired	(7)	(12,301)				(12,308)
Shares repurchased and retired (in Shares)	(704,997)
Equity-based compensation expense		6,767				6,767
Investment by non-controlling interests					4,939	4,939
Purchase of non-controlling interests		888			(893)	(5)
Currency translation adjustment and derivative transactions, net				9,398	313	9,711
Balance at Dec. 31, 2012	$ 390	$ 257,209	$ 426,457	$ 15,260	$ 16,804	$ 716,120
Balance (in Shares) at Dec. 31, 2012	38,952,561