Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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- Definition

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

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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

Represents the charge against earnings during the period for commitment fees and debt issuance expenses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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- Definition

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

+ References

No definition available.

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- Definition

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
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Subsequent Event Subsequent Event - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 26, 2015	Dec. 31, 2015	Dec. 31, 2014	Apr. 25, 2014	Jun. 18, 2007
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 400,000,000			$ 350,000,000
Debt Instrument, Interest Rate, Stated Percentage	3.70%			4.35%
3.70% Senior Notes due 2045
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 400,000,000	$ 400,000,000	$ 0
Debt Instrument, Interest Rate, Stated Percentage	3.70%	3.70%			6.70%
Proceeds from Debt, Net of Issuance Costs	$ 394,900,000
Debt Related Commitment Fees and Debt Issuance Costs	800,000
Unrealized Gain (Loss)	$ (12,900,000)	$ (12,900,000)