Summary of Significant Accounting Policies - Narrative (Details)
3 Months Ended 6 Months Ended
Jan. 01, 2020
USD ($)
Jun. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
segment
Dec. 31, 2019
USD ($)
Summary Of Significant Accounting Policies [Line Items]        
Net assets   $ 5,977,838,000 $ 5,977,838,000 $ 5,832,661,000
Net liabilities   2,694,030,000 $ 2,694,030,000 2,419,412,000
Number of segments | segment     1  
Rent escalators adjustment period     1 year  
Reserves for uncollectible amounts   7,200,000 $ 7,200,000 3,800,000
Accounts receivable   39,300,000 39,300,000 11,400,000
Reserve for losses   6,700,000 6,700,000 400,000
Deferred rental revenue receivables   95,800,000 95,800,000 84,000,000.0
Goodwill impairment     0  
Provision for income taxes     0  
Deferral rental income recognized CARES Act   22,300,000 $ 22,300,000  
Deferred rent average repayment period     12 months  
Minimum        
Summary Of Significant Accounting Policies [Line Items]        
Rent deferral period     1 month  
Maximum        
Summary Of Significant Accounting Policies [Line Items]        
Rent deferral period     6 months  
Average        
Summary Of Significant Accounting Policies [Line Items]        
Rent deferral period     3 months  
Accounting Standards Update 2016-13        
Summary Of Significant Accounting Policies [Line Items]        
Recognition of loss due to adoption of new guidance $ 300,000      
Loans receivable and real estate assets held under direct financing lease $ 40,300,000      
Special Purpose Entity        
Summary Of Significant Accounting Policies [Line Items]        
Net assets   350,000,000 $ 350,000,000 380,000,000
Net liabilities   $ 220,000,000 $ 220,000,000 $ 230,000,000