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Long-Term Debt - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Oct. 11, 2017 | Dec. 21, 2016 | Oct. 14, 2016 | Apr. 21, 2015
--- | --- | --- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |  |  |
Net unamortized debt issuance costs | $ (30,733) | $ (34,781) |  |  |  |
Less: current maturities of long term debt | (651) | (622) |  |  |  |
Debt reflected as long term | 2,086,765 | 2,038,321 |  |  |  |
Revolving credit agreement |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-tern debt |  | 0 |  |  |  |
Senior notes | 6.625% Senior Notes Due 2023 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-tern debt | 350,000 | $ 350,000 |  |  |  |
Net unamortized debt issuance costs | $ (4,400) |  |  |  |  |
Stated interest rate | 6.625% | 6.625% |  |  |  | 6.625%
Senior notes | 6.000% Senior Notes Due 2024 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-tern debt | $ 650,000 | $ 650,000 |  |  |  |
Net unamortized debt issuance costs | $ (8,700) |  |  |  |  |
Stated interest rate | 6.00% | 6.00% |  |  | 6.00% |
Senior notes | 6.375% Senior Notes Due 2025 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-tern debt | $ 600,000 | $ 600,000 |  |  |  |
Net unamortized debt issuance costs | $ (12,500) |  |  |  |  |
Stated interest rate | 6.375% | 6.375% |  | 6.375% |  |
Senior notes | 6.375% Senior Notes Due 2026 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-tern debt | $ 450,000 | $ 450,000 |  |  |  |
Net unamortized debt issuance costs | $ (5,000) |  |  |  |  |
Stated interest rate | 6.375% | 6.375% | 6.375% |  |  |
Construction loans |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-tern debt | $ 23,149 | $ 23,724 |  |  |  |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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