Schedule III - Real Estate and Related Depreciation (Details)	Dec. 31, 2017 USD ($) ft²
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	749,893
Initial cost, Land	$ 5,493,814
Initial cost, Buildings & Improvements	48,240,686
Costs Subsequent to Acquisition	2,721,305
Gross Carrying Amount, Land	5,493,814
Gross Carrying Amount, Buildings & Improvements	50,961,991
Total	56,455,805
Accumulated Depreciation	$ 2,187,530
Clinton, CT
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	30,338
Initial cost, Land	$ 356,040
Initial cost, Buildings & Improvements	3,108,285
Costs Subsequent to Acquisition	11,927
Gross Carrying Amount, Land	356,040
Gross Carrying Amount, Buildings & Improvements	3,120,212
Total	3,476,252
Accumulated Depreciation	$ 77,480
Bolingbrook, IL
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	111,200	[1]
Initial cost, Land	$ 633,914	[1]
Initial cost, Buildings & Improvements	5,491,409	[1]
Costs Subsequent to Acquisition	2,435,760	[1]
Gross Carrying Amount, Land	633,914	[1]
Gross Carrying Amount, Buildings & Improvements	7,927,169	[1]
Total	8,561,083	[1]
Accumulated Depreciation	$ 385,193	[1]
Dolton, IL
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	86,590
Initial cost, Land	$ 614,413
Initial cost, Buildings & Improvements	5,227,313
Costs Subsequent to Acquisition	9,611
Gross Carrying Amount, Land	614,413
Gross Carrying Amount, Buildings & Improvements	5,236,924
Total	5,851,337
Accumulated Depreciation	$ 280,457
McCordsville, IN
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	81,731
Initial cost, Land	$ 770,000
Initial cost, Buildings & Improvements	6,776,000
Costs Subsequent to Acquisition	46,578
Gross Carrying Amount, Land	770,000
Gross Carrying Amount, Buildings & Improvements	6,822,578
Total	7,592,578
Accumulated Depreciation	$ 214,964
Merrillville, IN
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	66,820	[1]
Initial cost, Land	$ 597,229	[1]
Initial cost, Buildings & Improvements	5,104,011	[1]
Costs Subsequent to Acquisition	94,605	[1]
Gross Carrying Amount, Land	597,229	[1]
Gross Carrying Amount, Buildings & Improvements	5,198,616	[1]
Total	5,795,845	[1]
Accumulated Depreciation	$ 273,892	[1]
Rochester, NY
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	68,017	[1]
Initial cost, Land	$ 571,583	[1]
Initial cost, Buildings & Improvements	5,227,630	[1]
Gross Carrying Amount, Land	571,583	[1]
Gross Carrying Amount, Buildings & Improvements	5,227,630	[1]
Total	5,799,213	[1]
Accumulated Depreciation	$ 240,570	[1]
Lima, OH
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	97,635
Initial cost, Land	$ 530,000
Initial cost, Buildings & Improvements	4,664,000
Costs Subsequent to Acquisition	91,036
Gross Carrying Amount, Land	530,000
Gross Carrying Amount, Buildings & Improvements	4,755,036
Total	5,285,036
Accumulated Depreciation	$ 157,579
Sadsburyville, PA
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	78,842	[1]
Initial cost, Land	$ 462,749	[1]
Initial cost, Buildings & Improvements	5,146,579	[1]
Costs Subsequent to Acquisition	1,539	[1]
Gross Carrying Amount, Land	462,749	[1]
Gross Carrying Amount, Buildings & Improvements	5,148,118	[1]
Total	5,610,867	[1]
Accumulated Depreciation	$ 269,580	[1]
Tuxis Self Storage I LLC | Millbrook, NY
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	12,480
Initial cost, Land	$ 313,950
Initial cost, Buildings & Improvements	2,723,468
Costs Subsequent to Acquisition	10,049
Gross Carrying Amount, Land	313,950
Gross Carrying Amount, Buildings & Improvements	2,733,517
Total	3,047,467
Accumulated Depreciation	$ 67,494
Tuxis Real Estate II LLC | Millbrook, NY
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	1,875
Initial cost, Land	$ 110,010
Initial cost, Buildings & Improvements	177,427
Gross Carrying Amount, Land	110,010
Gross Carrying Amount, Buildings & Improvements	177,427
Total	$ 287,437
SSG Summerville I LLC | Summerville, SC
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	72,700	[1]
Initial cost, Land	$ 345,160	[1]
Initial cost, Buildings & Improvements	2,989,159	[1]
Costs Subsequent to Acquisition	5,475	[1]
Gross Carrying Amount, Land	345,160	[1]
Gross Carrying Amount, Buildings & Improvements	2,994,634	[1]
Total	3,339,794	[1]
Accumulated Depreciation	$ 142,424	[1]
SSG Summerville II LLC | Summerville, SC
Real Estate And Accumulated Depreciation [Line Items]
Square Footage | ft²	41,665	[1]
Initial cost, Land	$ 188,766	[1]
Initial cost, Buildings & Improvements	1,605,405	[1]
Costs Subsequent to Acquisition	14,725	[1]
Gross Carrying Amount, Land	188,766	[1]
Gross Carrying Amount, Buildings & Improvements	1,620,130	[1]
Total	1,808,896	[1]
Accumulated Depreciation	$ 77,897	[1]

[1] This property is part of the Loan Agreement with a balance of $20,000,000 as of December 31, 2017.