Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2016	$ 1,207,358	$ 420	$ 416,816	$ 941,001	$ (150,879)
Beginning Balance (in shares) at Dec. 31, 2016	42,037	42,037
Net income	$ 41,074			41,074
Other comprehensive income:
Cumulative translation adjustment	28,778				28,778
Issuance of common stock in connection with:
Exercise of options	1,990	$ 1	1,989
Exercise of options (in shares)		57
Restricted share grants, less net settled shares of 87	(4,232)	$ 2	(4,234)
Restricted share grants, less net settled shares of 87 (in shares)		213
Stock units issued under incentive compensation plan	1,547		1,547
Purchase and retirement of common stock	(155,285)	$ (44)	(155,241)
Purchase and retirement of common stock (in shares)		(4,366)
Cumulative effect due to adoption of new accounting standard	(3,189)			(3,189)
Share-based compensation	12,888		12,888
Ending Balance at Sep. 30, 2017	$ 1,130,929	$ 379	$ 273,765	$ 978,886	$ (122,101)
Ending Balance (in shares) at Sep. 30, 2017	37,941	37,941