Consolidated Statements of Stockholders' Equity (Unaudited) - 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 (in shares) at Dec. 31, 2017	70,820,173		(8,448,874)
Beginning Balance at Dec. 31, 2017	$ 708	$ 459,816	$ (294,005)	$ (202,116)	$ 610,836	$ (21,198)	$ 554,041	$ 279	$ 554,320
Unrealized gain on interest rate swaps, net of tax						6,647	6,647		6,647
Foreign currency translation adjustment						6,179	6,179	10	6,189
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price withheld for employee taxes and strike price (in shares)	168,991
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 2	1,133					1,135		1,135
Net share settlement of restricted stock awards (in shares)			(30,028)
Net share settlement of restricted stock awards			$ (1,364)				(1,364)		(1,364)
Stock repurchases (in shares)			(560,000)
Stock repurchases			$ (25,656)				(25,656)		(25,656)
Cash dividends paid to noncontrolling interest of subsidiary								(314)	(314)
Share-based compensation		3,106					3,106		3,106
Redemption value adjustment					(7,665)		(7,665)		(7,665)	$ (7,665)
Net income					33,645		33,645	151	33,796	33,770
Balance (in shares) at Mar. 31, 2018	70,989,164		(9,038,902)
Ending Balance at Mar. 31, 2018	$ 710	464,055	$ (321,025)	(202,116)	636,816	(8,372)	570,068	126	570,194
Balance (in shares) at Dec. 31, 2018	71,186,418		(9,047,060)
Beginning Balance at Dec. 31, 2018	$ 712	476,116	$ (321,473)	(202,116)	831,123	(23,813)	760,549	712	761,261	761,261
Unrealized gain on interest rate swaps, net of tax						(5,124)	(5,124)		(5,124)
Foreign currency translation adjustment						(933)	(933)	55	(878)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price withheld for employee taxes and strike price (in shares)	209,143
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 2	1,681					1,683		1,683
Net share settlement of restricted stock awards (in shares)			(50,651)
Net share settlement of restricted stock awards			$ (2,642)				(2,642)		(2,642)
Stock repurchases (in shares)			0
Share-based compensation		3,594					3,594		3,594
Redemption value adjustment					2,432		2,432		2,432	2,432
Net income					44,861		44,861	643	45,504	45,769
Acquisition of business								4,125	4,125
Balance (in shares) at Mar. 31, 2019	71,395,561		(9,097,711)
Ending Balance at Mar. 31, 2019	$ 714	$ 481,391	$ (324,115)	$ (202,116)	$ 878,416	$ (29,870)	$ 804,420	$ 5,535	$ 809,955	$ 809,955