Fresh Start Accounting - Consolidated Balance Sheet (Parenthetical) (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended								9 Months Ended	12 Months Ended
	Mar. 31, 2017	Mar. 21, 2017	Nov. 30, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 21, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Fresh Start Adjustment [Line Items]
Liabilities subject to compromise				$ 0								$ 0
Fair value of equity issued in settlement of Senior Notes and certain general unsecured creditors		$ (948,944)					$ (948,944)
Long-term debt and capital leases, classified as current		4,632		3,273			4,632					3,273
Long-term debt and capital leases, less current maturities		291,429		141,386			291,429					141,386
Cancellation of predecessor equity - par value		450					450
Cancellation of predecessor equity - paid in capital		948,613		961,200			948,613					961,200
Professional fees												3,091
Total reorganization items	$ 620			$ 543	$ 858	$ 1,070						$ 3,091
Predecessor
Fresh Start Adjustment [Line Items]
Senior Notes and associated accrued interest		1,267,410					1,267,410	$ 1,267,410					$ 1,267,410
Accounts payable and accrued liabilities		6,687					6,687	9,212					9,212
Accrued payroll and benefits payable		3,949					3,949	4,048					4,048
Revenue distribution payable		3,050					3,050	3,474					3,474
Liabilities subject to compromise		1,281,096					1,281,096	1,284,144					1,284,144
Gain on settlement of liabilities subject to compromise							372,093
Write-off unamortized issuance costs associated with Prior Credit Facility							1,687
Long-term debt and capital leases, classified as current		468,814					468,814	469,112	[1]				469,112	[1]
Long-term debt and capital leases, less current maturities								0					0
Cancellation of predecessor equity - par value		14					14
Cancellation of predecessor equity - paid in capital		$ 425,425					425,425	425,231					425,231
Write-off unamortized issuance costs associated with Prior Credit Facility							(1,687)
Fresh start accounting adjustments							(641,684)
Professional fees							18,790						15,484
Claims for non-performance of executory contract													1,236
Rejection of employment contracts							4,573
Total reorganization items							(988,727)	$ 5,861		$ 5,504	$ 5,355		$ 16,720		$ 0
Common Stock
Fresh Start Adjustment [Line Items]
Common stock shares issued		44,982,142
Exit Revolver
Fresh Start Adjustment [Line Items]
Payment in full to extinguish Prior Credit Facility			$ (10,900)
Reorganization Adjustments
Fresh Start Adjustment [Line Items]
Cash proceeds from rights offering		$ 50,031
Payment in full to extinguish Prior Credit Facility		(444,440)
Payment of accrued interest on Prior Credit Facility		(2,095)
Payment of previously accrued creditor-related professional fees		(6,954)
Net cash used		(135,333)
Total issuance costs on Exit Credit Facility		2,410					2,410
Senior Notes and associated accrued interest		1,267,410					1,267,410
Accounts payable and accrued liabilities		6,687					6,687
Accrued payroll and benefits payable		3,949					3,949
Revenue distribution payable		3,050					3,050
Liabilities subject to compromise		1,281,096					1,281,096
Amounts settled in cash, reinstated or otherwise reserved at emergence		(10,089)					(10,089)
Fair value of equity issued in settlement of Senior Notes and certain general unsecured creditors		(898,914)					(898,914)
Gain on settlement of liabilities subject to compromise		372,093
Reclassification from current to noncurrent, based on scheduled repayment, of debt no longer in default		(22,612)					(22,612)
Write-off unamortized issuance costs associated with Prior Credit Facility		1,687
Long-term debt and capital leases, classified as current		(464,182)					(464,182)
Reclassification from current to noncurrent, based on scheduled repayment, of debt no longer in default		22,612					22,612
Long-term debt and capital leases, less current maturities		291,429					291,429
Cancellation of predecessor equity - par value		450					450
Cancellation of predecessor equity - paid in capital		948,613					948,613
Issuance of successor common stock in settlement of claims		898,914					898,914
Issuance of successor common stock under rights offering		50,031					50,031
Issuance of warrants		118					118
Net impact to common stock-par and additional paid in capital		523,624					523,624
Cancellation of predecessor equity		425,438
Write-off unamortized issuance costs associated with Prior Credit Facility		(1,687)
Net impact to retained earnings		795,844					795,844
Reorganization Adjustments | Predecessor
Fresh Start Adjustment [Line Items]
Cancellation of predecessor equity - par value		(14)					(14)
Cancellation of predecessor equity - paid in capital		$ (425,425)					(425,425)
Reorganization Adjustments | Common Stock
Fresh Start Adjustment [Line Items]
Common stock shares issued		44,982,142
Warrants issued for purchase of common stock	140,023
Reorganization Adjustments | Exit Credit Facility
Fresh Start Adjustment [Line Items]
Total issuance costs on Exit Credit Facility		$ 535					535
Reorganization Adjustments | Exit Term Loan
Fresh Start Adjustment [Line Items]
Cash proceeds		150,000
Fees paid to lender		(750)
Total issuance costs on Exit Credit Facility		750					750
Establishment of Exit Term Loan - current portion		1,183					1,183
Reorganization Adjustments | Exit Revolver
Fresh Start Adjustment [Line Items]
Cash proceeds		120,000
Fees paid to lender		(1,125)
Total issuance costs on Exit Credit Facility		1,125					1,125
Reorganization Adjustments | Exit Credit Facility | Exit Term Loan
Fresh Start Adjustment [Line Items]
Origination of the Exit Term Loan, net of current portion		148,817					148,817
Reorganization Adjustments | Exit Credit Facility | Exit Revolver
Fresh Start Adjustment [Line Items]
New credit facility, opening balance		$ 120,000					$ 120,000

[1] Senior Notes have not been included in this table as they were classified as “Liabilities subject to compromise” at December 31, 2016. Additionally, as a result of certain debt defaults which occurred in early 2016 and remained uncured during the pendency of the Chapter 11 Cases, all outstanding long-term debt was classified as current at December 31, 2016