Fair Value Measurements - Carrying Values and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	$ 1,985,758	$ 2,044,035
Credit Facility, Secured Due January 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	59,000	104,000
Term Loan, Secured, Due April 2024
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	973,247	975,000
Second Lien Notes, Secured, Due July 2024
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	578,072	545,000
6.875% Notes, Unsecured, Due April 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	150,439	195,035
7.125% Notes, Unsecured, Due April 2025
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	225,000	225,000
Level 2 \| Principal Repayment Obligation
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	1,985,758	2,044,035
Level 2 \| Estimated Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	1,063,837	1,495,137
Level 2 \| Credit Facility, Secured Due January 2022 \| Principal Repayment Obligation
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Credit facility	59,000	104,000
Level 2 \| Credit Facility, Secured Due January 2022 \| Estimated Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Credit facility	59,000	104,000
Level 2 \| Term Loan, Secured, Due April 2024 \| Principal Repayment Obligation
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Term loan	973,247	975,000
Level 2 \| Term Loan, Secured, Due April 2024 \| Estimated Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Term loan	729,935	858,000
Level 2 \| Second Lien Notes, Secured, Due July 2024 \| Principal Repayment Obligation
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	578,072	545,000
Level 2 \| Second Lien Notes, Secured, Due July 2024 \| Estimated Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	235,854	395,125
Level 2 \| 6.875% Notes, Unsecured, Due April 2022 \| Principal Repayment Obligation
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	150,439	195,035
Level 2 \| 6.875% Notes, Unsecured, Due April 2022 \| Estimated Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	16,548	68,262
Level 2 \| 7.125% Notes, Unsecured, Due April 2025 \| Principal Repayment Obligation
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	225,000	225,000
Level 2 \| 7.125% Notes, Unsecured, Due April 2025 \| Estimated Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	$ 22,500	$ 69,750

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Fair value portion of contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Fair value portion of contractual obligation to pay money on demand or on fixed or determinable dates.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Fair value portion of notes payable.

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