Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Deficit
Beginning balance (in shares) at Dec. 31, 2017		26,371,572		152,443
Beginning balance at Dec. 31, 2017	$ 338,653	$ 264	$ 439,517	$ (4,454)	$ (96,674)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of restricted stock (in shares)		272,510
Issuances of restricted stock	0	$ 2	(2)
Amortization of equity-classified share-based compensation	6,798		6,798
Treasury stock, net	(1,342)		(291)	$ (1,051)
Treasury stock, net (in shares)				69,337
Net loss	(30,531)				(30,531)
Ending balance (in shares) at Mar. 31, 2018		26,644,082		221,780
Ending balance at Mar. 31, 2018	313,578	$ 266	446,022	$ (5,505)	(127,205)
Beginning balance (in shares) at Dec. 31, 2017		26,371,572		152,443
Beginning balance at Dec. 31, 2017	338,653	$ 264	439,517	$ (4,454)	(96,674)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(97,921)
Ending balance (in shares) at Sep. 30, 2018		26,765,089		217,618
Ending balance at Sep. 30, 2018	261,010	$ 268	459,477	$ (4,140)	(194,595)
Beginning balance (in shares) at Mar. 31, 2018		26,644,082		221,780
Beginning balance at Mar. 31, 2018	313,578	$ 266	446,022	$ (5,505)	(127,205)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of restricted stock (in shares)		48
Issuances of restricted stock	2		2
Amortization of equity-classified share-based compensation	9,626		9,626
Treasury stock, net	(1)		(1,743)	$ 1,742
Treasury stock, net (in shares)				(48,400)
Net loss	(40,054)				(40,054)
Ending balance (in shares) at Jun. 30, 2018		26,644,130		173,380
Ending balance at Jun. 30, 2018	283,151	$ 266	453,907	$ (3,763)	(167,259)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of restricted stock (in shares)		120,959
Issuances of restricted stock	0	$ 2	(2)
Amortization of equity-classified share-based compensation	5,571		5,571
Treasury stock, net	(376)		1	$ (377)
Treasury stock, net (in shares)				44,238
Net loss	(27,336)				(27,336)
Ending balance (in shares) at Sep. 30, 2018		26,765,089		217,618
Ending balance at Sep. 30, 2018	261,010	$ 268	459,477	$ (4,140)	(194,595)
Beginning balance (in shares) at Dec. 31, 2018		26,990,034		242,322
Beginning balance at Dec. 31, 2018	219,428	$ 270	464,264	$ (3,835)	(241,271)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of restricted stock (in shares)		277,865
Issuances of restricted stock	0	$ 3	(3)
Amortization of equity-classified share-based compensation	3,275		3,275
Treasury stock, net	(343)		(163)	$ (180)
Treasury stock, net (in shares)				68,227
Net loss	(27,476)				(27,476)
Ending balance (in shares) at Mar. 31, 2019		27,267,899		310,549
Ending balance at Mar. 31, 2019	194,884	$ 273	467,373	$ (4,015)	(268,747)
Beginning balance (in shares) at Dec. 31, 2018		26,990,034		242,322
Beginning balance at Dec. 31, 2018	219,428	$ 270	464,264	$ (3,835)	(241,271)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(94,130)				(94,130)
Ending balance (in shares) at Sep. 30, 2019		27,912,059		2,965,374
Ending balance at Sep. 30, 2019	127,945	$ 279	471,648	$ (8,581)	(335,401)
Beginning balance (in shares) at Mar. 31, 2019		27,267,899		310,549
Beginning balance at Mar. 31, 2019	194,884	$ 273	467,373	$ (4,015)	(268,747)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of restricted stock (in shares)		644,160
Issuances of restricted stock	0	$ 6	(6)
Amortization of equity-classified share-based compensation	3,329		3,329
Treasury stock, net	(1,340)			$ (1,340)
Treasury stock, net (in shares)				596,194
Net loss	(27,777)				(27,777)
Ending balance (in shares) at Jun. 30, 2019		27,912,059		906,743
Ending balance at Jun. 30, 2019	169,096	$ 279	470,696	$ (5,355)	(296,524)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of restricted stock	0
Amortization of equity-classified share-based compensation	1,165		1,165
Treasury stock, net	(3,439)		(213)	$ (3,226)
Treasury stock, net (in shares)				2,058,631
Net loss	(38,877)				(38,877)
Ending balance (in shares) at Sep. 30, 2019		27,912,059		2,965,374
Ending balance at Sep. 30, 2019	$ 127,945	$ 279	$ 471,648	$ (8,581)	$ (335,401)