Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Noncontrolling Interest [Member]	Accumulated Other Comprehensive Loss
Common Stock, Dividends, Per Share, Cash Paid	$ 0.150
Beginning Balance, Issued Shares at Dec. 31, 2017		31,476,428
Beginning Balance, Value at Dec. 31, 2017		$ 3,148	$ 1,410	$ 510,975	$ 42,249	$ (24,023)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2017	$ 533,759
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	55,388			55,388
Net Income (Loss) Attributable to Noncontrolling Interest	139				139
Cumulative translation adjustment	(30,937)					(30,937)
Repurchase and retirement of common stock, Shares		(30,000)
Stock Issued During Period, Value, Stock Options Exercised	42	$ 0	42	0
Repurchase and retirement of common stock, Value	(2,226)	$ (3)	(1,339)	(884)
Vesting of restricted stock, Shares		25,957
Vesting of restricted stock, Value	0	$ 1	(1)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		2,283
Share based compensation	1,509		1,509
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(1,014)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(100)	$ 0	(100)
Recognized controlling ownership of joint venture	5,327		(787)		6,114
Dividends paid	(4,737)			(4,737)	0
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Calculated under Revenue Guidance in Effect before Topic 606 [Member]	(8,802)			(8,802)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | ASC 340-40 [Member]	(1,460)			(1,460)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2018	$ 547,902
Ending Balance, Issued Shares at Jun. 30, 2018		31,473,654
Ending Balance, Value at Jun. 30, 2018		$ 3,146	734	550,480	48,502	(54,960)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.075
Beginning Balance, Issued Shares at Mar. 31, 2018		31,458,976
Beginning Balance, Value at Mar. 31, 2018		$ 3,146	0	523,668	42,895	(28,782)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Mar. 31, 2018	$ 540,927
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	29,180			29,180
Net Income (Loss) Attributable to Noncontrolling Interest	(109)				(109)
Cumulative translation adjustment	(26,178)					(26,178)
Stock Issued During Period, Value, Stock Options Exercised	42	$ 0	42	0
Vesting of restricted stock, Shares		12,683
Vesting of restricted stock, Value	0	$ 0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		2,283
Share based compensation	756		756
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(288)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(64)	$ 0	(64)
Recognized controlling ownership of joint venture	5,716		0		5,716
Dividends paid	(2,368)			(2,368)	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2018	$ 547,902
Ending Balance, Issued Shares at Jun. 30, 2018		31,473,654
Ending Balance, Value at Jun. 30, 2018		$ 3,146	734	550,480	48,502	(54,960)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.150
Beginning Balance, Issued Shares at Dec. 31, 2018	30,567,725	30,567,725
Beginning Balance, Value at Dec. 31, 2018	$ 478,195	$ 3,057	3,397	535,118	66,242	(63,377)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2018	544,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	54,561			54,561
Net Income (Loss) Attributable to Noncontrolling Interest	(1,172)				(1,172)
Cumulative translation adjustment	7,893					7,893
Repurchase and retirement of common stock, Shares		(50,000)
Repurchase and retirement of common stock, Value	(2,172)	$ (5)	0	(2,167)
Vesting of restricted stock, Shares		12,586
Vesting of restricted stock, Value	0	$ 1	(1)
Share based compensation	1,422		1,422
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(471)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(27)	$ 0	(27)
Recognized controlling ownership of joint venture	(12,790)		398		(13,188)
Dividends paid	(4,599)			(4,599)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2019	$ 587,553
Ending Balance, Issued Shares at Jun. 30, 2019	30,529,840	30,529,840
Ending Balance, Value at Jun. 30, 2019	$ 535,671	$ 3,053	5,189	582,913	51,882	(55,484)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.075
Beginning Balance, Issued Shares at Mar. 31, 2019		30,523,756
Beginning Balance, Value at Mar. 31, 2019		$ 3,052	4,350	556,364	65,177	(59,895)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Mar. 31, 2019	$ 569,048
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	28,851			28,851
Net Income (Loss) Attributable to Noncontrolling Interest	(505)				(505)
Cumulative translation adjustment	4,411					4,411
Vesting of restricted stock, Shares		6,204
Vesting of restricted stock, Value	0	$ 1	(1)
Share based compensation	846		846
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		120
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(6)	$ 0	6
Recognized controlling ownership of joint venture	(12,790)		0		(12,790)
Dividends paid	(2,302)			2,302	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2019	$ 587,553
Ending Balance, Issued Shares at Jun. 30, 2019	30,529,840	30,529,840
Ending Balance, Value at Jun. 30, 2019	$ 535,671	$ 3,053	$ 5,189	$ 582,913	$ 51,882	$ (55,484)