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Long-Term Debt (Break-Down of Long-Term Debt) (Details) - USD ($) $ in Thousands | Sep. 30, 2017 | Dec. 31, 2016 | Dec. 21, 2016 | Oct. 31, 2016 | Oct. 14, 2016 | Jun. 04, 2015 | Apr. 21, 2015
--- | --- | --- | --- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |  |  |  |
Net unamortized debt issuance costs | $ (30,111) | $ (27,174) |  |  |  |  |
Less: current maturities of long term debt | (570) | (276) |  |  |  |  |
Long-term debt, net of current maturities | 1,958,136 | 1,593,599 |  |  |  |  |
Construction loans |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Net unamortized debt issuance costs | (100) |  |  |  |  |  |
7.75% Senior Notes due 2020 | Senior notes |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Long-term debt | $ 0 | 0 |  |  |  |  |
Stated interest rate, percent | 7.75% |  |  |  |  |  |
6.625% Senior Notes due 2023 | Senior notes |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Long-term debt | $ 350,000 | 350,000 |  |  |  |  |
Net unamortized debt issuance costs | $ (5,500) |  |  |  |  |  |
Stated interest rate, percent | 6.625% |  |  |  |  |  | 6.625%
6.000% Senior Notes due 2024 | Senior notes |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Long-term debt | $ 650,000 | 650,000 |  |  |  |  |
Net unamortized debt issuance costs | $ (10,200) |  |  |  |  |  |
Stated interest rate, percent | 6.00% |  |  | 6.00% | 6.00% |  |
6.375% Senior Notes due 2025 | Senior notes |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Long-term debt | $ 600,000 | 600,000 |  |  |  |  |
Net unamortized debt issuance costs | $ (14,300) |  |  |  |  |  |
Stated interest rate, percent | 6.375% |  | 6.375% |  |  |  |
Nova Scotia, Amegy, KeyBank | Revolving credit agreement | Amended and restated credit agreement |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Long-term debt | $ 365,000 | 0 |  |  |  |  |
InterBank | Revolving credit agreement | Construction loans |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Stated interest rate, percent |  |  |  |  |  | 4.50% |
InterBank | Letter of credit | Construction loans |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Long-term debt | $ 23,817 | $ 21,049 |  |  |  |  |

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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/presentationRef -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 2: http://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -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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