Investments - Operating Lease Asset (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) item	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Operating ground lease assets	$ 24,009,000		$ 24,254,000
Rental revenue	583,000	$ 508,000
Future minimum lease payments
Total lease liabilities - ground leases	29,130,000		$ 29,347,000
Ground lease by STORE capital
Future minimum lease payments
Long-term lease commitment	$ 16,500,000
Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Typical number of renewal options | item	1
Ground leases
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Operating ground lease assets	$ 24,000,000.0
Lease costs	600,000	524,000
Rental revenue	583,000	$ 508,000
Future minimum lease payments
2020	1,911,000
2021	2,378,000
2022	2,333,000
2023	6,083,000
2024	2,012,000
2025	1,699,000
Thereafter	33,973,000
Total lease payments	50,389,000
Less imputed interest	(26,173,000)
Total lease liabilities - ground leases	24,216,000
Ground leases | Ground lease by STORE capital
Future minimum lease payments
2020	23,000
2021	31,000
2022	31,000
2023	31,000
2024	31,000
2025	33,000
Thereafter	3,042,000
Total lease payments	3,222,000
Less imputed interest	(2,608,000)
Total lease liabilities - ground leases	614,000
Ground leases | Ground lease by STORE capital tenants
Future minimum lease payments
2020	1,888,000
2021	2,347,000
2022	2,302,000
2023	6,052,000
2024	1,981,000
2025	1,666,000
Thereafter	30,931,000
Total lease payments	47,167,000
Less imputed interest	(23,565,000)
Total lease liabilities - ground leases	$ 23,602,000