|
Senior Unsecured Notes (Summary Of Senior Unsecured Notes) (Details) (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2013
|
Dec. 31, 2012
|
|||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | $ 1,616,575 | $ 1,446,894 | ||||||||
|
4.600% Senior Unsecured Notes, Due June 15, 2013 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 99,987 | [1] | ||||||||
| Effective Rate | 4.742% | [1],[2] | ||||||||
| Interest rate of senior unsecured notes | 4.60% | [1] | ||||||||
| Maturity date of the senior unsecured notes | Jun. 15, 2013 | [1] | ||||||||
|
5.125% Senior Unsecured Notes, Due February 15, 2014 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 200,030 | [3] | 200,270 | [3] | ||||||
| Effective Rate | 5.11% | [2],[3] | ||||||||
| Interest rate of senior unsecured notes | 5.125% | [3] | ||||||||
| Maturity date of the senior unsecured notes | Feb. 15, 2014 | [3] | ||||||||
|
5.125% Senior Unsecured Notes, Due January 15, 2015 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 149,902 | 149,810 | ||||||||
| Effective Rate | 5.297% | [2] | ||||||||
| Interest rate of senior unsecured notes | 5.125% | |||||||||
| Maturity date of the senior unsecured notes | Jan. 15, 2015 | |||||||||
|
5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 200,161 | 200,237 | ||||||||
| Effective Rate | 5.806% | [2] | ||||||||
| Interest rate of senior unsecured notes | 5.80% | |||||||||
| Maturity date of the senior unsecured notes | Jan. 15, 2016 | |||||||||
|
2.500% Senior Unsecured Notes Due December 15, 2017 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 248,855 | 248,560 | ||||||||
| Effective Rate | 2.803% | [2] | ||||||||
| Interest rate of senior unsecured notes | 2.50% | |||||||||
| Maturity date of the senior unsecured notes | Dec. 15, 2017 | |||||||||
|
7.750% Senior Unsecured Notes, Due August 15, 2019 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 248,799 | 248,585 | ||||||||
| Effective Rate | 8.017% | [2] | ||||||||
| Interest rate of senior unsecured notes | 7.75% | |||||||||
| Maturity date of the senior unsecured notes | Aug. 15, 2019 | |||||||||
|
4.500% Senior Unsecured Notes Due April 18, 2022 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | 299,505 | 299,445 | ||||||||
| Effective Rate | 4.612% | [2] | ||||||||
| Interest rate of senior unsecured notes | 4.50% | |||||||||
| Maturity date of the senior unsecured notes | Apr. 18, 2022 | |||||||||
|
3.150% Senior Unsecured Note, Due May 15, 2023 [Member]
|
||||||||||
| Debt Instrument [Line Items] | ||||||||||
| Senior Unsecured Notes | $ 269,323 | |||||||||
| Effective Rate | 3.517% | [2] | ||||||||
| Interest rate of senior unsecured notes | 3.15% | |||||||||
| Maturity date of the senior unsecured notes | May 15, 2023 | |||||||||
|
||||||||||