Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Repurchased Stock	Additional Paid-In Capital	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2013		17,577,625
Beginning balance at Dec. 31, 2013	$ 207,069	$ 176		$ 164,913	$ 41,980
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for cash (in shares)		133,643
Stock issued for cash	537	$ 1		536
Stock issued for director compensation (in shares)		2,535
Stock issued for director compensation	90			90
Repurchased shares of common and restricted stock from stockholders (in shares)		(30,973)	(530,962)
Repurchased shares of common and restricted stock from stockholders	(19,712)		$ (18,470)	(1,242)
Stock-based compensation	$ 5,107			5,107
Repurchased and retired shares of common stock (in shares)	(530,962)	(530,962)	530,962
Repurchased and retired shares of common stock		$ (5)	$ 18,470		(18,465)
Excess tax benefit (expense) from stock based compensation	$ 250			250
Net income	40,877				40,877
Ending balance at Dec. 31, 2014	234,218	$ 172		169,654	64,392
Ending balance (in shares) at Dec. 31, 2014		17,151,868
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for cash (in shares)		213,921
Stock issued for cash	55	$ 1		54
Stock issued for director compensation (in shares)		2,248
Stock issued for director compensation	66			66
Repurchased shares of common and restricted stock from stockholders (in shares)		(56,272)	(1,322,846)
Repurchased shares of common and restricted stock from stockholders	(35,310)		$ (33,526)	(1,784)
Stock-based compensation	$ 6,229			6,229
Repurchased and retired shares of common stock (in shares)	(1,322,846)	(1,322,952)	1,322,846
Repurchased and retired shares of common stock		$ (13)	$ 33,526		(33,513)
Excess tax benefit (expense) from stock based compensation	$ (519)			(519)
Net income	32,414				32,414
Ending balance at Dec. 31, 2015	237,153	$ 160		173,700	63,293
Ending balance (in shares) at Dec. 31, 2015		15,988,813
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for cash (in shares)		167,270
Stock issued for cash	119	$ 1		118
Stock issued for director compensation (in shares)		2,322
Stock issued for director compensation	47			47
Repurchased shares of common and restricted stock from stockholders (in shares)		(49,512)
Repurchased shares of common and restricted stock from stockholders	(848)			(848)
Stock-based compensation	$ 5,164			5,164
Repurchased and retired shares of common stock (in shares)	0
Excess tax benefit (expense) from stock based compensation	$ (1,120)			(1,120)
Net income	24,155				24,155
Ending balance at Dec. 31, 2016	$ 264,670	$ 161		$ 177,061	$ 87,448
Ending balance (in shares) at Dec. 31, 2016		16,108,893