v2.4.0.8

Unsecured Senior Notes Unsecured Senior Notes (Narrative) (Details) (USD $) | 6 Months Ended | 0 Months Ended | 6 Months Ended | 0 Months Ended | 6 Months Ended
--- | --- | --- | --- | --- | ---
Jun. 30, 2013 | Jun. 30, 2012 | Jun. 30, 2013 Senior Notes [Member] | Apr. 11, 2013 3.279% Unsecured Senior Notes [Member] | Jun. 30, 2013 3.279% Unsecured Senior Notes [Member] | Jun. 27, 2013 3.916%t Unsecured Senior Notes [Member] | Jun. 30, 2013 3.916%t Unsecured Senior Notes [Member]
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Maximum Leverage Ratio |  |  | 60.00% |  |  |  |  |  |
Maximum Secured Debt Leverage Ratio |  |  | 50.00% |  |  |  |  |  |
Minimum Interest Coverage Ratio |  |  | 1.50 |  |  |  |  |  |
Minimum Unencumbered Asset Value Percentage Of Unsecured Debt |  |  | 150.00% |  |  |  |  |  |
Proceeds from Issuance of Unsecured Debt | $ 1,194,753,000 | $ 997,790,000 |  | $ 492,500,000 |  |  | $ 691,900,000 |  |
Debt Instrument, Face Amount |  |  |  | $ 500,000,000 |  |  | $ 700,000,000 |  |
Coupon/Stated Rate |  |  |  | 3.125% | 3.125% |  | 3.80% | 3.80% |
Senior Notes Pricing |  |  |  | 99.379% |  |  | 99.694% |  |
Effective Percentage |  |  |  | 3.279% | 3.279% | [1] | 3.916% | 3.916% | [1]
Debt Instrument, Maturity Date |  |  |  | Sep. 01, 2023 | Sep. 01, 2023 | [2] | Feb. 01, 2024 | Feb. 01, 2024 | [2]
[1] | Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs.
[2] | No principal amounts are due prior to maturity.

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- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: 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 Reference 2: 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=6584090&loc=d3e28878-108400 + Details
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- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: 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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: 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 + Details
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