Related Party Transactions - Related Party Acquisitions (Details) - Spirit MTA REIT - Affiliated Entity
12 Months Ended
Dec. 31, 2018
USD ($)
Property
Acquisition of Properties  
Related Party Transaction [Line Items]  
Number of properties assigned to related party | Property 3
Related Party Payment Received for Equalization for Capitalization Rate  
Related Party Transaction [Line Items]  
Related party transaction | $ $ 392,500