Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning Balance at Dec. 31, 2015	$ 252,432	$ 6	$ (52,207)	$ 213,566	$ (13,802)	$ 104,869
Balance (in shares) at Dec. 31, 2015		62,645,000	9,547,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income						3,949
Total other comprehensive loss, net of tax	(7,147)
Comprehensive income (loss)	(3,198)
Issuance of common stock upon exercise of stock awards	$ 1,770	$ 0		1,770
Issuance of common stock upon exercise of stock awards (in shares)	420,000	746,000
Issuance of treasury shares as consideration for acquisition	$ 2,012		$ 2,749			(737)
Issuance of treasury shares as consideration for acquisition (in shares)			244,000
Excess tax benefit derived from stock award exercises	3,572			3,572
Stock based compensation expense	5,572			5,572
Ending Balance at Dec. 31, 2016	262,161	$ 6	$ (49,458)	224,480	(20,949)	108,082
Balance (in shares) at Dec. 31, 2016		63,391,000	9,303,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income						16,430
Total other comprehensive loss, net of tax	1,720				1,720
Comprehensive income (loss)	18,150
Issuance of common stock upon exercise of stock awards	$ 1,421	$ 0		1,421
Issuance of common stock upon exercise of stock awards (in shares)	428,000	648,000
Issuance of treasury shares as consideration for acquisition	$ 4,678	$ 0	$ 4,561	385		(269)
Issuance of treasury shares as consideration for acquisition (in shares)		(36,000)	405,000
Acquisition of treasury shares	$ (10,976)		$ (10,976)
Acquisition of treasury shares (in shares)	1,121,928		1,122,000
Stock based compensation expense	$ 6,820			6,820
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	2,291			2,093
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2016-09 [Member]						198
Ending Balance at Dec. 31, 2017	284,545	$ 6	$ (55,873)	235,199	(19,229)	124,442
Balance (in shares) at Dec. 31, 2017		64,075,000	10,020,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income						(76,171)
Total other comprehensive loss, net of tax	(5,080)				(5,080)
Comprehensive income (loss)	(81,251)
Issuance of common stock upon exercise of stock awards	$ (541)	$ 0		(541)
Issuance of common stock upon exercise of stock awards (in shares)	662,000	420,000
Acquisition of treasury shares	$ (25,598)		$ (25,598)
Acquisition of treasury shares (in shares)	2,667,732		2,668,000
Stock based compensation expense	$ 5,302
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2014-09 [Member]	482					482
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2016-16 [Member]	152					152
Ending Balance at Dec. 31, 2018	$ 183,091	$ 6	$ (81,471)	$ 239,960	$ (24,309)	$ 48,905
Balance (in shares) at Dec. 31, 2018		64,495,000	12,688,000