Debt - Summary of Debt (Details) - USD ($)
$ in Thousands
9 Months Ended
Sep. 30, 2016
Aug. 18, 2016
Dec. 31, 2015
May 31, 2014
Debt Instrument [Line Items]        
Total debt, gross $ 3,803,650   $ 4,186,567  
Debt discount, net (54,975)   (52,203)  
Deferred financing costs, net (38,812)   (41,577)  
Total debt, net $ 3,709,863   4,092,787  
Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 4.94%      
Weighted average stated rates 4.34%      
Weighted average maturity 5 years 2 months 12 days      
Revolving Credit Facilities        
Debt Instrument [Line Items]        
Total debt, gross $ 105,000   0  
Revolving Credit Facilities | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 3.44%      
Weighted average stated rates 1.79%      
Weighted average maturity 2 years 6 months      
Term Loan        
Debt Instrument [Line Items]        
Total debt, gross $ 370,000   325,000  
Deferred financing costs, net $ (1,600)   (2,100)  
Term Loan | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 2.17%      
Weighted average stated rates 1.88%      
Weighted average maturity 2 years 1 month 6 days      
Senior Unsecured Notes        
Debt Instrument [Line Items]        
Weighted average stated rates   4.45%    
Total debt, gross $ 300,000   0  
Deferred financing costs, net $ (2,900)      
Senior Unsecured Notes | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 4.64%      
Weighted average stated rates 4.45%      
Weighted average maturity 10 years      
Master Trust Notes        
Debt Instrument [Line Items]        
Total debt, gross $ 1,677,660   1,692,094  
Debt discount, net (19,829)   (22,909)  
Deferred financing costs, net (17,138)   (19,345)  
Total debt, net $ 1,640,693   1,649,840  
Master Trust Notes | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 5.58%      
Weighted average stated rates 5.03%      
Weighted average maturity 6 years 6 months      
CMBS - fixed-rate        
Debt Instrument [Line Items]        
Total debt, gross $ 603,490   1,360,215  
CMBS - fixed-rate | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 4.91%      
Weighted average stated rates 5.63%      
Weighted average maturity 3 years 8 months 12 days      
CMBS - variable-rate        
Debt Instrument [Line Items]        
Total debt, gross $ 0   61,758  
CMBS - variable-rate | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 0.00%      
Weighted average stated rates 0.00%      
Weighted average maturity 0 years      
Convertible Notes        
Debt Instrument [Line Items]        
Total debt, gross $ 747,500   747,500  
Deferred financing costs, net $ (12,200)   $ (14,700) $ (19,600)
Convertible Notes | Weighted Average        
Debt Instrument [Line Items]        
Weighted average effective interest rates 5.31%      
Weighted average stated rates 3.28%      
Weighted average maturity 3 years 6 months