Quarterly report pursuant to Section 13 or 15(d)

Senior Unsecured Notes (Summary Of Senior Unsecured Notes) (Details)

v3.2.0.727
Senior Unsecured Notes (Summary Of Senior Unsecured Notes) (Details) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2015
Dec. 31, 2014
Debt Instrument [Line Items]    
Senior Unsecured Notes $ 1,268,293 $ 1,267,744
5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]    
Debt Instrument [Line Items]    
Senior Unsecured Notes $ 200,047 200,086
Effective rate [1] 5.806%  
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 $ 249,298 249,150
Effective rate [1] 2.803%  
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 $ 249,120 249,013
Effective rate [1] 8.017%  
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 $ 299,595 299,565
Effective rate [1] 4.612%  
Interest rate of senior unsecured notes 4.50%  
Maturity date of the senior unsecured notes Apr. 18, 2022  
3.150% Senior Unsecured Notes, Due May 15, 2023 [Member]    
Debt Instrument [Line Items]    
Senior Unsecured Notes $ 270,233 $ 269,930
Effective rate [1] 3.517%  
Interest rate of senior unsecured notes 3.15%  
Maturity date of the senior unsecured notes May 15, 2023  
[1] Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.