Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Interest Rate Cap [Member]	Interest Rate Swap [Member]	Common Stock (0.01 Par) [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit)	Treasury Stock at Cost [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member] Interest Rate Cap [Member]	Accumulated Other Comprehensive Loss [Member] Interest Rate Swap [Member]
Net Income (Loss) Attributable to Parent	$ 12,891
Balance at Dec. 31, 2016	167,593			$ 172	$ 106,803	$ 93,708	$ (11,628)	$ (21,462)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,891					12,891
Foreign currency translation adjustments	6,686							6,686
Change in fair value of derivative instrument, net of tax		$ (142)	$ 63						$ (142)	$ 63
Repurchases of common stock in the open market	(4,302)						(4,302)
Stock-based compensation expense	3,589				3,589
Shares withheld in exchange for tax withholding payments on stock-based compensation	(1,168)				(1,168)
Issuance of stock for employer contributions to retirement plan	2,725				40		2,685
Net issuances of stock pursuant to stock compensation plans and other	119				(2,008)		2,127
Balance at Dec. 31, 2017	188,054			172	107,256	106,599	(11,118)	(14,855)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjusted balance	187,658			172	107,256	106,203	(11,118)	(14,855)
Net Income (Loss) Attributable to Parent	9,836
Net income	9,836					9,836
Foreign currency translation adjustments	(6,914)							(6,914)
Change in fair value of derivative instrument, net of tax		$ 142	$ (63)						$ 142	$ (63)
Repurchases of common stock in the open market	(7,993)						(7,993)
Stock-based compensation expense	1,350				1,350
Shares withheld in exchange for tax withholding payments on stock-based compensation	(416)				(416)
Issuance of stock for employer contributions to retirement plan	2,960				(867)		3,827
Net issuances of stock pursuant to stock compensation plans and other	9				(1,473)		1,482
Balance at Dec. 31, 2018	186,569			172	105,850	116,039	(13,802)	(21,690)
Net Income (Loss) Attributable to Parent	15,189
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,189					15,189
Foreign currency translation adjustments	1,955							1,955
Stock-based compensation expense	2,617				2,617
Shares withheld in exchange for tax withholding payments on stock-based compensation	(278)				(278)
Issuance of stock for employer contributions to retirement plan	2,978				(2,251)		5,229
Net issuances of stock pursuant to stock compensation plans and other	884				(3,619)		4,503
Balance at Dec. 31, 2019	$ 209,914			$ 172	$ 102,319	$ 131,228	$ (4,070)	$ (19,735)