Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock	Total
Balance, beginning of period at Dec. 31, 2014	$ 22,183	$ 396,989	$ (129,413)	$ (3,019)	$ 286,740
Balance (in shares) at Dec. 31, 2014	22,182,972			110,874
Increase (Decrease) in Stockholders' Equity
Issuances of restricted stock and stock units	$ 291	(291)
Issuances of restricted stock and stock units (in shares)	291,075
Forfeiture of restricted stock	$ (21)	21
Forfeiture of restricted stock (in shares)	(20,973)
Shares repurchased to satisfy tax obligations	$ (9)	(113)			(122)
Shares repurchased to satisfy tax obligations (in shares)	(9,046)
Share-based compensation		3,113			3,113
Net income (loss)			11,950		11,950
Balance, end of period at Dec. 31, 2015	$ 22,444	399,719	(117,463)	$ (3,019)	301,681
Balance (in shares) at Dec. 31, 2015	22,444,028			110,874
Increase (Decrease) in Stockholders' Equity
Issuances of restricted stock and stock units	$ 347	(347)
Issuances of restricted stock and stock units (in shares)	347,400
Forfeiture of restricted stock	$ (155)	155
Forfeiture of restricted stock (in shares)	(155,027)
Shares repurchased to satisfy tax obligations	$ (12)	(176)			(188)
Shares repurchased to satisfy tax obligations (in shares)	(12,895)
Share-based compensation		2,207			2,207
Net income (loss)			147,107		147,107
Balance, end of period at Dec. 31, 2016	$ 22,624	401,558	29,644	$ (3,019)	450,807
Balance (in shares) at Dec. 31, 2016	22,623,506			110,874
Increase (Decrease) in Stockholders' Equity
Issuances of restricted stock and stock units	$ 40	(40)
Issuances of restricted stock and stock units (in shares)	40,051
Forfeiture of restricted stock	$ (176)	176
Forfeiture of restricted stock (in shares)	(175,972)
Shares repurchased to satisfy tax obligations	$ (13)	(200)			(213)
Shares repurchased to satisfy tax obligations (in shares)	(12,764)
Share-based compensation		3,365	(53)		3,312
Net income (loss)			(21,936)		(21,936)
Balance, end of period at Dec. 31, 2017	$ 22,475	$ 404,859	$ 7,655	$ (3,019)	$ 431,970
Balance (in shares) at Dec. 31, 2017	22,474,821			110,874