Schedule IV - Summary of Mortgage Loans on Real Estate (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) carWash earlyChildhoodEducationCenter state convenienceStore casualDiningRestaurant familyDiningRestaurant entertainmentCenter quickServiceRestaurant industrialFacility	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Face Amount of Mortgages	$ 234,713
Carrying Amount of Mortgages	$ 233,978	$ 181,419	$ 144,048	$ 87,029
First Mortgage Loans | Two Early Childhood Education Centers located in Florida
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of early childhood education centers | earlyChildhoodEducationCenter	2
Interest Rate	8.80%
Final Payment Terms	$ 12,000
Face Amount of Mortgages	12,000
Carrying Amount of Mortgages	$ 11,884
First Mortgage Loans | Two Early Childhood Education Centers located in Florida
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of early childhood education centers | earlyChildhoodEducationCenter	2
Interest Rate	8.53%
Final Payment Terms	$ 7,300
Face Amount of Mortgages	7,300
Carrying Amount of Mortgages	$ 7,226
First Mortgage Loans | Sixty-nine Quick Service Restaurants located in fifteen states
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of quick service restaurants | quickServiceRestaurant	69
Number of states | state	15
Interest Rate	7.79%
Final Payment Terms	$ 51,000
Face Amount of Mortgages	51,000
Carrying Amount of Mortgages	$ 50,995
First Mortgage Loans | One Early Childhood Education Center located in Florida
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of early childhood education centers | earlyChildhoodEducationCenter	1
Interest Rate	8.42%
Final Payment Terms	$ 5,300
Face Amount of Mortgages	5,300
Carrying Amount of Mortgages	$ 5,251
First Mortgage Loans | Three Convenience Stores located in Minnesota
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of convenience stores | convenienceStore	3
Interest Rate	8.54%
Final Payment Terms	$ 2,324
Face Amount of Mortgages	2,324
Carrying Amount of Mortgages	$ 2,317
First Mortgage Loans | One Family Dining Restaurant located in Georgia
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of family dining restaurant | familyDiningRestaurant	1
Interest Rate	7.00%
Final Payment Terms	$ 600
Face Amount of Mortgages	600
Carrying Amount of Mortgages	$ 596
First Mortgage Loans | Three Convenience Stores located in three states
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of convenience stores | convenienceStore	3
Interest Rate	8.30%
Final Payment Terms	$ 3,146
Face Amount of Mortgages	3,146
Carrying Amount of Mortgages	$ 3,063
First Mortgage Loans | Two Casual Dining Restaurants located in Kentucky and Ohio
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of casual dining restaurants | casualDiningRestaurant	2
Interest Rate	6.87%
Final Payment Terms	$ 2,520
Face Amount of Mortgages	2,520
Carrying Amount of Mortgages	$ 2,520
First Mortgage Loans | Three Casual Dining Restaurants located in three states
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of states | state	3
Number of casual dining restaurants | casualDiningRestaurant	3
Interest Rate	7.51%
Final Payment Terms	$ 2,673
Face Amount of Mortgages	2,673
Carrying Amount of Mortgages	$ 2,657
First Mortgage Loans | Two Convenience Stores located in Iowa
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of convenience stores | convenienceStore	2
Interest Rate	8.29%
Final Payment Terms	$ 2,389
Face Amount of Mortgages	2,389
Carrying Amount of Mortgages	$ 2,323
First Mortgage Loans | One Entertainment Center located in New Jersey
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of entertainment center | entertainmentCenter	1
Interest Rate	8.96%
Face Amount of Mortgages	$ 24,100
Carrying Amount of Mortgages	$ 24,090
First Mortgage Loans | Two Industrial facilities located in California
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of industrial facilities | industrialFacility	2
Interest Rate	7.44%
Final Payment Terms	$ 9,808
Face Amount of Mortgages	9,808
Carrying Amount of Mortgages	$ 9,785
First Mortgage Loans | Five Car Washes located in Nevada
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of car washes | carWash	5
Interest Rate	7.30%
Final Payment Terms	$ 25,714
Face Amount of Mortgages	25,714
Carrying Amount of Mortgages	$ 25,711
First Mortgage Loans | One Car Wash located in Florida
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of car washes | carWash	1
Interest Rate	7.73%
Final Payment Terms	$ 2,470
Face Amount of Mortgages	2,470
Carrying Amount of Mortgages	$ 2,464
First Mortgage Loans | One Casual Dining Restaurant located in Michigan
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of casual dining restaurants | casualDiningRestaurant	1
Interest Rate	8.00%
Final Payment Terms	$ 1,754
Face Amount of Mortgages	1,754
Carrying Amount of Mortgages	$ 1,710
First Mortgage Loans | Thirty-seven Quick Service Restaurants located in three states
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of quick service restaurants | quickServiceRestaurant	37
Number of states | state	3
Interest Rate	7.00%
Final Payment Terms	$ 26,307
Face Amount of Mortgages	26,307
Carrying Amount of Mortgages	$ 26,185
First Mortgage Loans | One Car Wash located in New Jersey
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of car washes | carWash	1
Interest Rate	7.73%
Final Payment Terms	$ 3,600
Face Amount of Mortgages	3,600
Carrying Amount of Mortgages	$ 3,592
First Mortgage Loans | One Convenience Store located in Minnesota
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of convenience stores | carWash	1
Interest Rate	8.30%
Final Payment Terms	$ 760
Face Amount of Mortgages	760
Carrying Amount of Mortgages	$ 740
First Mortgage Loans | One Car Wash located in Nevada
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of car washes | carWash	1
Interest Rate	7.33%
Final Payment Terms	$ 4,960
Face Amount of Mortgages	4,960
Carrying Amount of Mortgages	$ 4,948
First Mortgage Loans | One Car Wash located in Nevada
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of car washes | carWash	1
Interest Rate	7.43%
Final Payment Terms	$ 4,800
Face Amount of Mortgages	4,800
Carrying Amount of Mortgages	$ 4,789
First Mortgage Loans | Four Car Washes located in three states
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of states | state	3
Number of car washes | carWash	4
Interest Rate	8.64%
Final Payment Terms	$ 12,250
Face Amount of Mortgages	12,250
Carrying Amount of Mortgages	$ 12,246
First Mortgage Loans | Ten Car Washes located in five states
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Description Information [Abstract]
Number of states | state	5
Number of car washes | carWash	10
Interest Rate	8.93%
Final Payment Terms	$ 28,938
Face Amount of Mortgages	28,938
Carrying Amount of Mortgages	$ 28,886