Related Party Transactions - Related Party Property Management and Servicing Agreement and Asset Management Agreement (Details) - Affiliated entity - Spirit Realty, L.P. - Property Management and Servicing Agreement - USD ($) $ in Millions	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Aug. 31, 2019	Sep. 30, 2018	Aug. 31, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Property management fee, percent fee			0.25%
Servicing fee, percentage			0.75%
Management fee expense	$ 1.0	$ 1.6	$ 4.0	$ 4.6
Servicing fees	$ 0.3	$ 0.2	$ 1.1	$ 0.5
Due to related parties					$ 0.5