Financial Instruments - Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Carrying Amount	[1]		$ 402,062
Fair Value	[1]		403,000
Oil and Natural Gas Derivatives
Debt Instrument [Line Items]
Carrying Amount		$ 74,923	(66,830)
Fair Value		74,923	(66,830)
11.00% Second-Priority Senior Secured Notes – due April 2022
Debt Instrument [Line Items]
Carrying Amount		381,229
Fair Value		362,168
7.50% Senior Secured Notes – due May 2022
Debt Instrument [Line Items]
Carrying Amount		6,060
Fair Value		5,151
11.00% Bridge Loans – due April 2022
Debt Instrument [Line Items]
Carrying Amount	[1]		169,838
Fair Value	[1]		172,023
9.75% Senior Notes – due July 2022
Debt Instrument [Line Items]
Carrying Amount	[1]		100,681
Fair Value	[1]		102,000
9.75% Senior Notes – due February 2018
Debt Instrument [Line Items]
Carrying Amount			24,977
Fair Value			$ 24,977
Bank Credit Facility – due May 2022
Debt Instrument [Line Items]
Carrying Amount	[1]	257,448
Fair Value	[1]	$ 265,000

[1] The carrying amounts are net of discount and deferred financing costs.