Related Party Transactions and Arrangements - Asset Management Agreement and Interim Management Agreement (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 20, 2019
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Related Party Transaction [Line Items]          
Related party fee income   $ 178 $ 54,795 $ 678 $ 68,971
Asset Management Agreement | Spirit MTA REIT          
Related Party Transaction [Line Items]          
Receive termination fee $ 48,200        
Asset Management Agreement | Spirit MTA REIT | General and Administrative Expense          
Related Party Transaction [Line Items]          
Related party fee income     500   900
Interim Management Agreement | Spirit MTA REIT          
Related Party Transaction [Line Items]          
Agreement termination date       Sep. 20, 2019  
Asset Management Fees | Spirit MTA REIT          
Related Party Transaction [Line Items]          
Related party fee income   $ 200 $ 4,400 $ 700 $ 14,400
Initial one-year term | Interim Management Agreement | Spirit MTA REIT          
Related Party Transaction [Line Items]          
Due from related parties 1,000        
Renewal Term | Interim Management Agreement | Spirit MTA REIT          
Related Party Transaction [Line Items]          
Due from related parties $ 4,000