Summary of Operations and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Earnings Per Share [Abstract]

Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Table Text Block]

	Year Ended December 31,
	2012		2011		2010
Basic
Weighted average number of common shares outstanding
used in computing basic earnings per share		45,780		45,202		44,146
Net income attributable to common stockholders	$	24,152	$	50,737	$	76,733
Basic earnings per share attributable
to common stockholders	$	0.53	$	1.12	$	1.74
Diluted
Weighted average number of common shares outstanding
used in computing basic earnings per share		45,780		45,202		44,146
Add: Assumed exercise of stock options and stock awards		1,119		1,511		1,400
Weighted average number of common shares outstanding
used in computing diluted earnings per share		46,899		46,713		45,546
Net income attributable to common stockholders	$	24,152	$	50,737	$	76,733
Diluted earnings per share attributable
to common stockholders	$	0.51	$	1.09	$	1.68

Comprehensive Income [Abstract]

Schedule Of Accumulated Other Comprehensive Income Loss [Table Text Block]

	2012	2011
Translation adjustment	$ (22,663)	$ (29,919)
Unrealized loss on defined benefit plan	$ (11,254)	$ (5,843)