Summary of Operations and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Earnings Per Share [Abstract]

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

	Year Ended December 31,
	2013		2012		2011
Basic
Weighted average number of common shares outstanding
used in computing basic earnings per share		46,363		45,780		45,202
Net income attributable to common stockholders	$	26,532	$	24,152	$	50,737
Basic earnings per share attributable
to common stockholders	$	0.57	$	0.53	$	1.12
Diluted
Weighted average number of common shares outstanding
used in computing basic earnings per share		46,363		45,780		45,202
Add: Assumed exercise of stock options and stock awards		1,295		1,119		1,511
Weighted average number of common shares outstanding
used in computing diluted earnings per share		47,658		46,899		46,713
Net income attributable to common stockholders	$	26,532	$	24,152	$	50,737
Diluted earnings per share attributable
to common stockholders	$	0.56	$	0.51	$	1.09

Comprehensive Income [Abstract]

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

	2013	2012
Translation adjustment	$ (16,210)	$ (22,663)
Unrealized loss on defined benefit plan	$ (28,164)	$ (11,193)