Emergence from Chapter 11 and Fresh Start Accounting - Liabilities Subject to Compromise (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Fresh-Start Adjustment [Line Items]
Liabilities subject to compromise	$ 979,437
To reinstate the outstanding principal amount of Term Loan under the Amended and Restated Term Loan Facility.
Fresh-Start Adjustment [Line Items]
Recoveries pursuant to the prepackaged plan	(164,175)
To reinstate claim deemed to be accrued and unpaid interest under the Amended and Restated Term Loan.
Fresh-Start Adjustment [Line Items]
Recoveries pursuant to the prepackaged plan	(1,866)
Record issuance of equity to holders of Unsecured Notes
Fresh-Start Adjustment [Line Items]
Recoveries pursuant to the prepackaged plan	(273,103)
Recoveries pursuant to the Prepackaged Plan
Fresh-Start Adjustment [Line Items]
Recoveries pursuant to the prepackaged plan	(439,144)
Net Gain on Debt Discharge
Fresh-Start Adjustment [Line Items]
Net gain on debt discharge	540,293
Outstanding Unsecured Notes
Fresh-Start Adjustment [Line Items]
Liabilities subject to compromise, debt	775,000
Liabilities subject to compromise, accrued interest	38,396
Term Loan
Fresh-Start Adjustment [Line Items]
Liabilities subject to compromise, debt	164,175
Liabilities subject to compromise, accrued interest	$ 1,866