Debt - Estimated Fair Value of Our Long-Term Debt, not Including Effect of Unamortized Debt Issuance Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Less: Current maturities of long-term debt	$ (362,493)	$ 0
Long-term debt	3,577,863	3,877,402
Carrying Value
Debt Instrument [Line Items]
Long-term debt	3,940,356	3,877,402
Less: Current maturities of long-term debt	(362,493)	0
Long-term debt	3,577,863	3,877,402
Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	2,562,432	2,920,806
Less: Current maturities of long-term debt	(359,956)	0
Long-term debt	$ 2,202,476	2,920,806
4.90% Senior Notes due August 2020
Debt Instrument [Line Items]
Interest rate on senior notes	4.90%
4.625% Senior Notes due March 2021
Debt Instrument [Line Items]
Interest rate on senior notes	4.625%
3.95% Senior Notes due March 2022
Debt Instrument [Line Items]
Interest rate on senior notes	3.95%
7.75% Senior Notes due January 2024
Debt Instrument [Line Items]
Interest rate on senior notes	7.75%
7.95% Senior Notes due April 2025
Debt Instrument [Line Items]
Interest rate on senior notes	7.95%
6.20% Senior Notes due August 2040
Debt Instrument [Line Items]
Interest rate on senior notes	6.20%
6.05% Senior Notes due March 2041
Debt Instrument [Line Items]
Interest rate on senior notes	6.05%
5.25% Senior Notes due March 2042
Debt Instrument [Line Items]
Interest rate on senior notes	5.25%
8.95% Senior Notes due April 2045
Debt Instrument [Line Items]
Interest rate on senior notes	8.95%
Senior unsecured notes \| 4.90% Senior Notes due August 2020
Debt Instrument [Line Items]
Interest rate on senior notes	4.90%
Senior unsecured notes \| 4.90% Senior Notes due August 2020 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 62,493	65,810
Senior unsecured notes \| 4.90% Senior Notes due August 2020 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 59,956	60,177
Senior unsecured notes \| 4.625% Senior Notes due March 2021
Debt Instrument [Line Items]
Interest rate on senior notes	4.625%
Senior unsecured notes \| 4.625% Senior Notes due March 2021 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 79,837	92,967
Senior unsecured notes \| 4.625% Senior Notes due March 2021 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 71,287	84,931
Senior unsecured notes \| 3.95% Senior Notes due March 2022
Debt Instrument [Line Items]
Interest rate on senior notes	3.95%
Senior unsecured notes \| 3.95% Senior Notes due March 2022 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 21,178	41,617
Senior unsecured notes \| 3.95% Senior Notes due March 2022 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 16,320	37,096
Senior unsecured notes \| 7.75% Senior Notes due January 2024
Debt Instrument [Line Items]
Interest rate on senior notes	7.75%
Senior unsecured notes \| 7.75% Senior Notes due January 2024 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 389,430	783,350
Senior unsecured notes \| 7.75% Senior Notes due January 2024 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 265,495	613,719
Senior unsecured notes \| 7.95% Senior Notes due April 2025
Debt Instrument [Line Items]
Interest rate on senior notes	7.95%
Senior unsecured notes \| 7.95% Senior Notes due April 2025 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 446,848	446,517
Senior unsecured notes \| 7.95% Senior Notes due April 2025 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 285,818	339,035
Senior unsecured notes \| 7.875% Senior Notes due February 2026
Debt Instrument [Line Items]
Interest rate on senior notes	7.875%
Senior unsecured notes \| 7.875% Senior Notes due February 2026 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 739,037	738,075
Senior unsecured notes \| 7.875% Senior Notes due February 2026 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 567,525	647,085
Senior unsecured notes \| 6.20% Senior Notes due August 2040
Debt Instrument [Line Items]
Interest rate on senior notes	6.20%
Senior unsecured notes \| 6.20% Senior Notes due August 2040 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 390,506	390,454
Senior unsecured notes \| 6.20% Senior Notes due August 2040 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 175,281	245,242
Senior unsecured notes \| 6.05% Senior Notes due March 2041
Debt Instrument [Line Items]
Interest rate on senior notes	6.05%
Senior unsecured notes \| 6.05% Senior Notes due March 2041 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 389,780	389,693
Senior unsecured notes \| 6.05% Senior Notes due March 2041 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 172,295	247,171
Senior unsecured notes \| 5.25% Senior Notes due March 2042
Debt Instrument [Line Items]
Interest rate on senior notes	5.25%
Senior unsecured notes \| 5.25% Senior Notes due March 2042 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 478,090	477,996
Senior unsecured notes \| 5.25% Senior Notes due March 2042 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 206,230	277,056
Senior unsecured notes \| 8.95% Senior Notes due April 2045
Debt Instrument [Line Items]
Interest rate on senior notes	8.95%
Senior unsecured notes \| 8.95% Senior Notes due April 2045 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 390,739	390,672
Senior unsecured notes \| 8.95% Senior Notes due April 2045 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	213,908	311,392
Seller loans \| Seller-financed secured loan due September 2022 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	62,418	60,251
Seller loans \| Seller-financed secured loan due September 2022 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	51,095	57,902
Seller loans \| Seller-financed secured loan due February 2023 \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	55,000	0
Seller loans \| Seller-financed secured loan due February 2023 \| Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	42,222	0
Credit Facility \| Line of credit \| 2015 Credit Facility matures January 2020 \| Carrying Value
Debt Instrument [Line Items]
Credit facilities	300,000	0
Credit Facility \| Line of credit \| 2015 Credit Facility matures January 2020 \| Estimated Fair Value
Debt Instrument [Line Items]
Credit facilities	300,000	0
Credit Facility \| Line of credit \| 2017 Credit Facility matures January 2023 \| Carrying Value
Debt Instrument [Line Items]
Credit facilities	135,000	0
Credit Facility \| Line of credit \| 2017 Credit Facility matures January 2023 \| Estimated Fair Value
Debt Instrument [Line Items]
Credit facilities	$ 135,000	$ 0

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

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.

+ References

No definition available.

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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.

+ References

Reference 1: 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))
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-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ 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)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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