Related Party Transactions - Related Party Notes Receivable (Details) - Spirit MTA REIT - Affiliated Entity - Master Trust 2014 Series 2017-1 - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Related Party Transaction [Line Items] | ||
| Percentage of economic interest | 5.00% | |
| Outstanding principal balance | $ 33.5 | |
| Repayment premium related parties | 0.9 | |
| Interest income earned from related parties note | $ 1.1 | $ 0.9 |