Quarterly report pursuant to Section 13 or 15(d)

Senior Unsecured Notes (Details)

v3.5.0.2
Senior Unsecured Notes (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2016
Jun. 30, 2016
Dec. 31, 2015
Debt Instrument [Line Items]      
Principal balance outstanding $ 2,256,955,000 $ 2,256,955,000 $ 2,145,393,000
Gain from extinguishment of debt (12,420,000) (12,420,000)  
Total senior unsecured notes, net $ 2,274,798,000 $ 2,274,798,000 2,154,920,000
5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]      
Debt Instrument [Line Items]      
Interest rate of senior unsecured notes 5.80% 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]      
Interest rate of senior unsecured notes 2.50% 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]      
Interest rate of senior unsecured notes 7.75% 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]      
Interest rate of senior unsecured notes 4.50% 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]      
Interest rate of senior unsecured notes 3.15% 3.15%  
Maturity date of the senior unsecured notes   May 15, 2023  
Unsecured Note [Member]      
Debt Instrument [Line Items]      
Principal balance outstanding $ 1,075,000,000 $ 1,075,000,000 1,275,000,000
Adjustment for unamortized debt discount (5,578,000) (5,578,000) (6,156,000)
Unamortized deferred financing costs (4,480,000) (4,480,000) (5,062,000)
Total senior unsecured notes, net 1,064,942,000 1,064,942,000 1,263,782,000
Unsecured Note [Member] | 5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]      
Debt Instrument [Line Items]      
Principal balance outstanding $ 200,000,000 $ 200,000,000 200,000,000 [1]
Effective rate [1],[2] 5.806% 5.806%  
Interest rate of senior unsecured notes 5.80% 5.80%  
Maturity date of the senior unsecured notes   Jan. 15, 2016  
Unsecured Note [Member] | 2.500% Senior Unsecured Notes Due December 15, 2017 [Member]      
Debt Instrument [Line Items]      
Principal balance outstanding $ 250,000,000 $ 250,000,000 250,000,000
Effective rate [2] 2.803% 2.803%  
Unsecured Note [Member] | 7.750% Senior Unsecured Notes, Due August 15, 2019 [Member]      
Debt Instrument [Line Items]      
Principal balance outstanding $ 250,000,000 $ 250,000,000 250,000,000
Effective rate [2] 8.017% 8.017%  
Unsecured Note [Member] | 4.500% Senior Unsecured Notes Due April 18, 2022 [Member]      
Debt Instrument [Line Items]      
Principal balance outstanding $ 300,000,000 $ 300,000,000 300,000,000
Effective rate [2] 4.612% 4.612%  
Unsecured Note [Member] | 3.150% Senior Unsecured Notes, Due May 15, 2023 [Member]      
Debt Instrument [Line Items]      
Principal balance outstanding $ 275,000,000 $ 275,000,000 $ 275,000,000
Effective rate [2] 3.517% 3.517%  
[1] On January 15, 2016, the Company repaid these notes at their maturity using proceeds from a new unsecured term loan and borrowings under the Company's unsecured revolving credit facility.
[2] Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.