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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13476-108611

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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.

+ References

No definition available.

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Fair Value of Financial Instruments (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 32,900	$ 34,781
Senior notes \| 6.625% Senior Notes due 2023
Debt Instrument [Line Items]
Unamortized debt issuance costs	4,800
Senior notes \| 6.000% Senior Notes due 2024
Debt Instrument [Line Items]
Unamortized debt issuance costs	9,400
Senior notes \| 6.375% Senior Notes due 2025
Debt Instrument [Line Items]
Unamortized debt issuance costs	13,200
Senior notes \| 6.375% Senior Notes Due 2026
Debt Instrument [Line Items]
Unamortized debt issuance costs	5,400
Carry value \| Senior notes
Debt Instrument [Line Items]
Carrying value of notes	2,000,000
Fair value \| Senior notes
Debt Instrument [Line Items]
Carrying value of notes	$ 2,000,000