Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balance at Dec. 31, 2014	$ 109	$ 14,550	$ 77,985	$ 88	$ 92,732
Beginning balance, shares at Dec. 31, 2014	10,903,341
Tax shortfall associated with stock-based compensation arrangements		(24)			(24)
Restricted stock grants, net of forfeitures	$ 1	(1)
Restricted stock grants, net of forfeitures, shares	123,836
Stock-based compensation		10,213			10,213
Change in fair value of derivative instrument, net of income tax				$ (88)	(88)
Net income			40,023		40,023
Ending balance at Dec. 31, 2015	$ 110	24,738	118,008		142,856
Ending balance, shares at Dec. 31, 2015	11,027,177
Tax shortfall associated with stock-based compensation arrangements		(51)			(51)
Restricted stock grants, net of forfeitures	$ 1	(1)
Restricted stock grants, net of forfeitures, shares	66,312
Stock-based compensation		10,767			10,767
Net income			34,802		34,802
Ending balance at Dec. 31, 2016	$ 111	35,453	152,810		188,374
Ending balance, shares at Dec. 31, 2016	11,093,489
Restricted stock grants, net of forfeitures	$ 1	(1)
Restricted stock grants, net of forfeitures, shares	73,936
Stock-based compensation		11,627			11,627
Common stock dividends			(11,416)		(11,416)
Net income			20,612		20,612
Ending balance at Dec. 31, 2017	$ 112	$ 47,079	$ 162,006		$ 209,197
Ending balance, shares at Dec. 31, 2017	11,167,425