Fresh Start Accounting - Narrative (Details) $ / shares in Units, $ in Thousands	Apr. 22, 2016 USD ($) $ / shares shares
Fresh-Start Adjustment [Line Items]
Enterprise Value	$ 473,660
Discount Rate on Risk Adjusted After Tax Cash Flows	0.12
Number of series of warrants issued	2
Warrant issued, percentage of the reorganized Company's equity	15.00%
Number of shares of common stock called by warrant | shares	4,300,000.0
Warrant, fair value (usd per share) | $ / shares	$ 3.49
Expected dividend rate (percent)	0.00%
Debtor-in-Possession Financing, Amount Arranged	$ 75,000
Value of Equity Issuance for DIP Credit Agreement	$ 142,300
Common shares issued (in shares) | shares	10,000,000
Plan or Reorganization, warrants existing equity holders	30.00%
Value of warrants issued	$ 15,000
Fair Value of Proved Reserves	509,400
Fair Value of Probable Reserves	45,500
Minimum [Member]
Fresh-Start Adjustment [Line Items]
Enterprise Value	460,000
Maximum [Member]
Fresh-Start Adjustment [Line Items]
Enterprise Value	800,000
New Credit Facility [Member]
Fresh-Start Adjustment [Line Items]
Net proceeds from debt issuance	253,000
Payments of debt issuance costs	7,000
Prior First Lean Credit Facility [Member]
Fresh-Start Adjustment [Line Items]
Repayments of debt	$ 289,500
2019 Warrants [Member]
Fresh-Start Adjustment [Line Items]
Number of shares of common stock called by warrant | shares	2,142,857
Exercise price of warrant (usd per share) | $ / shares	$ 80.00
Warrant, fair value (usd per share) | $ / shares	3.26
Warrant, strike price (usd per share) | $ / shares	$ 80
Expected volatility rate (percent)	70.00%
Risk free interest rate (percent)	1.01%
Expected term	3 years
2020 Warrants [Member]
Fresh-Start Adjustment [Line Items]
Number of shares of common stock called by warrant | shares	2,142,857
Exercise price of warrant (usd per share) | $ / shares	$ 86.18
Warrant, fair value (usd per share) | $ / shares	3.73
Warrant, strike price (usd per share) | $ / shares	$ 86.18
Expected volatility rate (percent)	65.00%
Risk free interest rate (percent)	1.19%
Expected term	4 years
Reorganization Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Impairment of short-term leasehold improvement build-out receivable	$ (600)
Net settlement of predecessor accounts payable	5,200
Reorganization Adjustments [Member] | New Credit Facility [Member]
Fresh-Start Adjustment [Line Items]
Net proceeds from debt issuance	253,000
Payments of debt issuance costs	6,482
Debt issuance costs	6,984
Accounts Payable and Accrued Liabilities [Member] | Reorganization Adjustments [Member] | New Credit Facility [Member]
Fresh-Start Adjustment [Line Items]
Debt issuance costs	$ 500
Former Holders of Senior Notes [Member]
Fresh-Start Adjustment [Line Items]
Per share value | $ / shares	$ 21.44
Holders of General Unsecured and Retiree Committee Unsecured Claims [Member]
Fresh-Start Adjustment [Line Items]
Common shares issued (in shares) | shares	8,850,000.00
Backstop Parties [Member]
Fresh-Start Adjustment [Line Items]
Common shares issued (in shares) | shares	750,000.00
Former Shareholders [Member]
Fresh-Start Adjustment [Line Items]
Common shares issued (in shares) | shares	400,000.0