CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2017		27,707,328
Beginning balance at Dec. 31, 2017	$ 28,526	$ 3	$ 22,968	$ 5,555
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	753		753
Exercise of RSUs and stock options (in shares)		152,088
Exercise of RSUs	209	$ 0	209
Net income (loss)	36,257			36,257
Shares repurchased (in shares)		(686,492)
Shares repurchased	(2,024)	$ 0		(2,024)
Accretion of Series A-1 preferred stock	(925)		(925)
Ending balance (in shares) at Jun. 30, 2018		27,172,924
Ending balance at Jun. 30, 2018	64,668	$ 3	23,005	41,660
Beginning balance (in shares) at Mar. 31, 2018		27,719,828
Beginning balance at Mar. 31, 2018	59,688	$ 3	22,361	37,324
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	435		435
Exercise of RSUs and stock options (in shares)		139,588
Exercise of RSUs	209	$ 0	209
Net income (loss)	7,039			7,039
Shares repurchased (in shares)		(686,492)
Shares repurchased	(2,023)	$ 0		(2,023)
Ending balance (in shares) at Jun. 30, 2018		27,172,924
Ending balance at Jun. 30, 2018	64,668	$ 3	23,005	41,660
Beginning balance (in shares) at Dec. 31, 2018		27,568,656
Beginning balance at Dec. 31, 2018	54,679	$ 3	28,534	26,142
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	497		497
Exercise of RSUs and stock options (in shares)		41,864
Exercise of RSUs		$ 0
Net income (loss)	(7,972)			(7,972)
Accretion of Series A-1 preferred stock	0
Ending balance (in shares) at Jun. 30, 2019		27,610,520
Ending balance at Jun. 30, 2019	47,204	$ 3	29,031	18,170
Beginning balance (in shares) at Mar. 31, 2019		27,595,840
Beginning balance at Mar. 31, 2019	48,923	$ 3	28,780	20,140
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	251		251
Exercise of RSUs and stock options (in shares)		14,680
Exercise of RSUs		$ 0
Net income (loss)	(1,970)			(1,970)
Ending balance (in shares) at Jun. 30, 2019		27,610,520
Ending balance at Jun. 30, 2019	$ 47,204	$ 3	$ 29,031	$ 18,170