Write-off of amounts previously capitalized as debt issuance costs as part of an extinguishment of debt.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the weighted average interest rate on notes payable during the period.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

When presenting a range of interest rates, the highest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

+ 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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

+ References

+ Details

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Period Type:	instant

- Definition

Maximum contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- Definition

Minimum contractual interest rate for funds borrowed, under the debt agreement.

+ 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(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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.

+ Details

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- Definition

Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ 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(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Period Type:	duration

- Definition

Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ 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(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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- Definition

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.

+ References

Reference 1: 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

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 SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 13, 16
-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for a borrowing supported by a written promise to pay an obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3291-108585

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Balance Type:	credit
Period Type:	duration

- Details

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Debt Notes (Details) - USD ($) $ in Thousands	12 Months Ended
Debt Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt		$ 750,000	$ 500,000
Debt Instrument, Basis Spread on Variable Rate	0.00%
Repayments of Notes Payable	$ 300,000	1,250,000	$ 400,000
Summary of Company's unsecured note balances and certain interest rate and maturity date information
Notes, net	$ 5,876,352	5,425,346
6.584% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.584%
Repayments of Notes Payable	$ 300,000
3.375% Notes [Member] [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt	$ 450,000
Debt Instrument, Interest Rate, Stated Percentage	3.375%
Proceeds from Debt, Net of Issuance Costs	$ 447,500
Debt Instrument, Interest Rate, Effective Percentage Rate Range, Maximum	3.81%
4.50% Notes [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt	$ 300,000	$ 750,000
Debt Instrument, Interest Rate, Stated Percentage	4.50%	4.50%
Proceeds from Debt, Net of Issuance Costs	$ 298,900	$ 744,700
Debt Instrument, Interest Rate, Effective Percentage Rate Range, Maximum	4.55%	4.57%
5.250% Notes [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.25%
Repayments of Notes Payable		$ 500,000
DelayedDrawTermLoan [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable		750,000
Write-off of unamortized deferred financing costs		600
2.375% Notes [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt	$ 450,000	$ 450,000
Debt Instrument, Interest Rate, Stated Percentage	2.375%	2.375%
Debt Instrument, Basis Spread on Variable Rate	0.61%
Proceeds from Debt, Net of Issuance Costs		$ 449,600
Debt Instrument, Interest Rate, Effective Percentage Rate Range, Maximum		2.52%
Fixed Rate Public or Private Notes [Member]
Summary of Company's unsecured note balances and certain interest rate and maturity date information
Notes, net	$ 5,423,012	$ 4,974,154
Weighted Average Interest Rate	5.30%	5.45%
Floating Rate Public or Private Notes [Member]
Summary of Company's unsecured note balances and certain interest rate and maturity date information
Notes, net	$ 453,340	$ 451,192
Weighted Average Interest Rate	0.93%	1.15%
2.375% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.61%
Fixed Rate Public or Private Notes [Member]
Summary of Company's unsecured note balances and certain interest rate and maturity date information
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	3.00%	3.00%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.57%	7.57%
Debt Instrument, Maturity Date Range, Start	Jan. 01, 2016	Jan. 01, 2015
Debt Instrument, Maturity Date Range, End	Dec. 31, 2045	Dec. 31, 2044
Floating Rate Public or Private Notes [Member]
Summary of Company's unsecured note balances and certain interest rate and maturity date information
Debt Instrument, Maturity Date Range, Start	Jan. 01, 2019	Jan. 01, 2019
Debt Instrument, Maturity Date Range, End	Dec. 31, 2019	Dec. 31, 2019
London Interbank Offered Rate (LIBOR) [Member] \| 2.375% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR plus .61%	LIBOR plus .61%