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	$ 0.225
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	84,630			84,630
Net Income (Loss) Attributable to Noncontrolling Interest	178				178
Cumulative translation adjustment	(61,810)					(61,810)
Repurchase and retirement of common stock, Shares		(30,000)
Repurchase and retirement of common stock, Value	(2,226)	$ (3)	(1,339)	(884)
Vesting of restricted stock, Shares		53,956
Vesting of restricted stock, Value	0	$ 5	(5)
Share based compensation	2,240		2,240
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(1,638)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(147)	$ 0	(147)
Recognized controlling ownership of joint venture	2,292		(787)		3,079
Dividends paid	(7,106)			(7,106)	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 Sep. 30, 2018	541,590
Ending Balance, Issued Shares at Sep. 30, 2018		31,501,029
Ending Balance, Value at Sep. 30, 2018		$ 3,150	1,414	577,353	45,506	(85,833)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		2,283
Stock Issued During Period, Value, Stock Options Exercised	42	$ 0	42
Beginning Balance, Issued Shares at Jun. 30, 2018		31,473,654
Beginning Balance, Value at Jun. 30, 2018		$ 3,146	734	550,480	48,502	(54,960)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2018	547,902
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	29,242
Net Income (Loss) Attributable to Noncontrolling Interest	39
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2018	$ 541,590
Ending Balance, Issued Shares at Sep. 30, 2018		31,501,029
Ending Balance, Value at Sep. 30, 2018		$ 3,150	1,414	577,353	45,506	(85,833)
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	75,070			75,070
Net Income (Loss) Attributable to Noncontrolling Interest	(6,617)				(6,617)
Cumulative translation adjustment	(10,859)					(10,859)
Repurchase and retirement of common stock, Shares		(95,000)
Repurchase and retirement of common stock, Value	(4,152)	$ (10)	0	(4,142)
Vesting of restricted stock, Shares		19,144
Vesting of restricted stock, Value	0	$ 2	(2)
Share based compensation	2,451		2,451
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(662)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(36)	$ 0	(36)
Recognized controlling ownership of joint venture	(10,080)		398		(10,478)
Dividends paid	(6,898)			(6,898)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2019	$ 583,316
Ending Balance, Issued Shares at Sep. 30, 2019	30,491,207	30,491,207
Ending Balance, Value at Sep. 30, 2019	$ 534,169	$ 3,049	6,208	599,148	49,147	(74,236)
Beginning Balance, Issued Shares at Jun. 30, 2019		30,529,840
Beginning Balance, Value at Jun. 30, 2019		$ 3,053	5,189	582,913	51,882	(55,484)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2019	587,553
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	20,509			20,509
Net Income (Loss) Attributable to Noncontrolling Interest	(5,445)				(5,445)
Cumulative translation adjustment	(18,752)					(18,752)
Repurchase and retirement of common stock, Shares		(45,000)
Repurchase and retirement of common stock, Value	(1,980)	$ (5)	0	(1,975)
Vesting of restricted stock, Shares		6,558
Vesting of restricted stock, Value	0	$ 1	(1)
Share based compensation	1,029		1,029
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(191)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(9)	$ 0	(9)
Recognized controlling ownership of joint venture	2,710				2,710
Dividends paid	(2,299)			(2,299)	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2019	$ 583,316
Ending Balance, Issued Shares at Sep. 30, 2019	30,491,207	30,491,207
Ending Balance, Value at Sep. 30, 2019	$ 534,169	$ 3,049	$ 6,208	$ 599,148	$ 49,147	$ (74,236)