Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive (Loss) Income	Treasury Stock
Treasury stock, shares							(384,220)
Common stock, shares issued			12,891,317
Preferred stock, shares outstanding		0
BALANCE at Dec. 31, 2014	$ 26,450	$ 0	$ 13	$ 85,750	$ (54,799)	$ 62	$ (4,576)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	47,241				47,241
Exercise of warrants (in shares)			88,097
Exercise of warrants	309			309
Repurchase of common stock (in shares)							(547,042)
Repurchase of common stock	(16,071)						$ (16,071)
Shares issued for stock-based compensation awards (in shares)							91,060
Shares issued for stock-based compensation awards	666			(182)	(380)		$ 1,228
Dividends declared	(1,709)				(1,709)
Elimination of CTA upon dissolution	(82)					(82)
Foreign currency translation adjustments	(79)					(79)
Unrealized loss on available-for-sale securities	(2)					(2)
Stock-based compensation	86			86
BALANCE at Dec. 31, 2015	56,809	$ 0	$ 13	85,963	(9,647)	(101)	$ (19,419)
Treasury stock, shares							(840,202)
Common stock, shares issued			12,979,414
Preferred stock, shares outstanding		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 55,086				55,086
Repurchase of common stock (in shares)	(903,031)						(903,031)
Repurchase of common stock	$ (23,704)						$ (23,704)
Shares issued for stock-based compensation awards (in shares)							51,015
Shares issued for stock-based compensation awards	1,741			507			$ 1,234
Dividends declared	(6,891)				(6,891)
Elimination of CTA upon dissolution	132					132
Foreign currency translation adjustments	(838)					(838)
Unrealized loss on available-for-sale securities	0
Stock-based compensation	104			104
BALANCE at Dec. 31, 2016	$ 82,439	$ 0	$ 13	86,574	38,548	(807)	$ (41,889)
Treasury stock, shares	(1,692,218)						(1,692,218)
Common stock, shares issued	12,979,414		12,979,414
Preferred stock, shares outstanding		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 23,578				23,578
Adjustments to Additional Paid in Capital, Other				(5)
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited							(1,566)
Stock Issued During Period, Value, Restricted Stock Award, Forfeitures							$ (33)
Restricted Stock Award, Forfeitures	(38)
Shares issued for stock-based compensation awards (in shares)							56,260
Shares issued for stock-based compensation awards	1,431			79			$ 1,352
Dividends declared	(17,218)				(17,218)
Elimination of CTA upon dissolution	(258)					(258)
Foreign currency translation adjustments	677					677
Unrealized loss on available-for-sale securities	(25)					(25)
Stock-based compensation	35			35
BALANCE at Dec. 31, 2017	$ 90,621	$ 0	$ 13	$ 86,683	$ 44,908	$ (413)	$ (40,570)
Treasury stock, shares	(1,637,524)						(1,637,524)
Common stock, shares issued	12,979,414		12,979,414
Preferred stock, shares outstanding		0