Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Excess Purchase Price over Predecessor Basis [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total [Member]	Total
Balance	$ 696	$ 443,109	$ (111,516)	$ (202,116)	$ 358,173	$ (22,475)	$ 465,871		$ 465,871
Balance (in shares) at Dec. 31, 2015	69,582,669		(3,567,575)
Beginning Balance at Dec. 31, 2015	$ 696	443,109	$ (111,516)	(202,116)	358,173	(22,475)	465,871		465,871
Impact of adoption of certain accounting standards (Note 2) at Dec. 31, 2015					(2,299)		(2,299)		(2,299)
Balance at Dec. 31, 2015	696	443,109	(111,516)	(202,116)	355,874	(22,475)	463,572		463,572
Acquisition of business								53	53
Net unrealized gain on derivatives						535	535		535	$ 535
Foreign currency translation adjustment						(18,545)	(18,545)	13	(18,532)	(18,545)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	678,812
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 6	(11,473)					(11,467)		(11,467)
Net share settlement of restricted stock awards (in shares)			(28,593)
Net share settlement of restricted stock awards			$ (949)				(949)		(949)
Stock repurchases (in shares)			(3,968,706)
Stock repurchases			$ (149,937)				(149,937)		(149,937)
Excess tax benefits from equity awards		7,920					7,920		7,920
Share-based compensation		9,493					9,493		9,493
Pension liability adjustment						322	322		322	322
Redemption value adjustment					(909)		(909)		(909)	(909)
Net income					97,154		97,154	(76)	97,078	97,178
Ending Balance at Dec. 31, 2016	$ 702	449,049	$ (262,402)	(202,116)	452,119	(40,163)	397,189	(10)	397,179
Balance (in shares) at Dec. 31, 2016	70,261,481		(7,564,874)
Balance	$ 696	443,109	$ (111,516)	(202,116)	358,173	(40,163)	465,871		465,871
Balance	702	449,049	(262,402)	(202,116)	452,119	(40,163)	397,189	(10)	397,179
Net unrealized gain on derivatives						3,712	3,712		3,712	3,712
Foreign currency translation adjustment						15,191	15,191	(14)	15,177	15,191
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	558,692
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 6	2,686					2,692		2,692
Net share settlement of restricted stock awards (in shares)			(39,500)
Net share settlement of restricted stock awards			$ (1,591)				(1,591)		(1,591)
Stock repurchases (in shares)			(844,500)
Stock repurchases			$ (30,012)				(30,012)		(30,012)
Share-based compensation		10,205					10,205		10,205
Pension liability adjustment						62	62		62	62
Redemption value adjustment					909		909		909	909
Net income					157,808		157,808	119	157,927	159,557
Change in noncontrolling interest share								184
Change in noncontrolling interest share		(2,124)					(2,124)		(1,940)
Ending Balance at Dec. 31, 2017	$ 708	459,816	$ (294,005)	(202,116)	610,836	(21,198)	554,041	279	554,320	554,320
Balance (in shares) at Dec. 31, 2017	70,820,173		(8,448,874)
Balance	$ 702	449,049	$ (262,402)	(202,116)	452,119	(21,198)	397,189	(10)	397,179	554,320
Balance	708	459,816	(294,005)	(202,116)	610,836	(21,198)	554,041	279	554,320	554,320
Net unrealized gain on derivatives						2,924	2,924		2,924	2,924
Foreign currency translation adjustment						(5,976)	(5,976)	(2)	(5,978)	(5,976)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	366,245
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 4	1,737					1,741		1,741
Net share settlement of restricted stock awards (in shares)			(38,186)
Net share settlement of restricted stock awards			$ (1,812)				(1,812)		(1,812)
Stock repurchases (in shares)			(560,000)
Stock repurchases			$ (25,656)				(25,656)		(25,656)
Share-based compensation		14,563					14,563		14,563
Pension liability adjustment						437	437		437	437
Redemption value adjustment					(17,970)		(17,970)		(17,970)	(17,970)
Net income					238,257		238,257	749	239,006	241,220
Ending Balance at Dec. 31, 2018	712	476,116	(321,473)	(202,116)	831,123	(23,813)	760,549	712	761,261	761,261
Cash dividends paid to noncontrolling interest of subsidiary								(314)	(314)
Balance (in shares) at Dec. 31, 2018	71,186,418		(9,047,060)
Balance	$ 708	459,816	$ (294,005)	(202,116)	610,836	(21,198)	554,041	279	554,320	761,261
Balance	$ 712	$ 476,116	$ (321,473)	$ (202,116)	$ 831,123	$ (23,813)	$ 760,549	$ 712	$ 761,261	$ 761,261