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Amount, after accumulated amortization, of debt discount.

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Long-term Debt - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Sep. 15, 2016
Debt Instrument [Line Items]
Less: unamortized deferred financing costs on senior unsecured notes	$ (29,000)
Total long-term debt	2,097,606	$ 2,297,214
OMP Credit Facility
Debt Instrument [Line Items]
Long-term line of credit	78,000
Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes	2,052,950	2,052,950
Less: unamortized deferred financing costs on senior unsecured notes	(22,956)	(28,268)
Senior unsecured notes \| 7.25% senior unsecured notes due February 1, 2019
Debt Instrument [Line Items]
Total principal of senior unsecured notes	54,275	54,275
Senior unsecured notes \| 6.5% senior unsecured notes due November 1, 2021
Debt Instrument [Line Items]
Total principal of senior unsecured notes	395,501	395,501
Senior unsecured notes \| 6.875% senior unsecured notes due March 15, 2022
Debt Instrument [Line Items]
Total principal of senior unsecured notes	937,080	937,080
Senior unsecured notes \| 6.875% senior unsecured notes due January 15, 2023
Debt Instrument [Line Items]
Total principal of senior unsecured notes	366,094	366,094
Senior unsecured notes \| 2.625% senior unsecured convertible notes due September 15, 2023
Debt Instrument [Line Items]
Total principal of senior unsecured notes	300,000	300,000
Less: unamortized debt discount on senior unsecured convertible notes	$ (80,388)	(90,468)	$ (93,200)
Oasis Credit Facility \| Oasis Credit Facility \| Oasis Credit Facility
Debt Instrument [Line Items]
Total principal of senior unsecured notes		363,000
Oasis Credit Facility \| Oasis Credit Facility \| OMP Credit Facility
Debt Instrument [Line Items]
Total principal of senior unsecured notes		$ 0