Principal Activity and Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2015 USD ($) ft² property entity item shares	Dec. 31, 2014 USD ($) shares
Real Estate Properties [Line Items]
No. of properties \| property	146
Impairment losses related to the unconsolidated affiliates	$ 0	$ 0
Percentage of interest	100.00%
Cash contribution	$ 644
Property contribution	$ 1,316
Number of limited liability companies assessed as variable interest entity in which Company is not the primary beneficiary \| entity	1
Number of investments in tenant in common that do not qualify as variable interest entities and do not meet the control requirements for consolidation \| item	4
Total Assets held by unconsolidated affiliates	$ 32,296	32,459
Mortgage notes held by unconsolidated affiliates	20,421	20,803
Total Assets	594,509	532,263
Allowance for uncollectible receivables	0	0
Impairment of intangible assets	$ 0	0
Taxable income to be distributed	90.00%
Retainable taxable income	10.00%
Provisions or liabilities for income taxes	$ 0
Revenue from tenant rents and related activities	95.00%
Term of lease	1 year
Increase in revenue due to straight - line adjustment	$ 325	186
Straight - line Receivable	$ 2,863	$ 2,538
Denominators for the basic and diluted earnings per common share \| shares	7,223,000	5,507,000
Operating Partnership
Real Estate Properties [Line Items]
Percentage of interest	82.50%
Commercial Property
Real Estate Properties [Line Items]
No. of properties \| property	49
Residential Property
Real Estate Properties [Line Items]
No. of properties \| property	97
Real Estate Investments.
Real Estate Properties [Line Items]
Total Assets	$ 594,509
Assets Held for Sale
Real Estate Properties [Line Items]
No. of properties \| property	1
Multi-tenant apartment
Real Estate Properties [Line Items]
Residential, multi-tenant apartment complex, Units \| item	61
Grand Forks INREIT, LLC
Real Estate Properties [Line Items]
Percentage of interest	50.00%
Area (others) \| ft²	183,000
Michigan Street Transit Center, LLC ("Transit Center")
Real Estate Properties [Line Items]
Percentage of interest	99.00%
Mortgages [Member] \| INREIT Highland LLC
Real Estate Properties [Line Items]
Mortgage Carrying Amount	$ 2,259	$ 2,323
Amount to be Repaid	909	935
Mortgages [Member] \| Grand Forks INREIT, LLC
Real Estate Properties [Line Items]
Mortgage Carrying Amount	11,079	11,260
Amount to be Repaid	5,540	5,630
Mortgages [Member] \| INREIT Properties, LLLP
Real Estate Properties [Line Items]
Amount to be Repaid	4,722	4,814
Mortgages [Member] \| INREIT Properties, LLLP \| Building One
Real Estate Properties [Line Items]
Mortgage Carrying Amount	$ 7,083	$ 7,221
North Dakota \| Tenant in common - Office building, Fargo, North Dakota
Real Estate Properties [Line Items]
Percentage of interest	66.67%
Area (others) \| ft²	75,000
Highland Meadows, LLC, Bismarck, North Dakota \| INREIT Highland LLC
Real Estate Properties [Line Items]
Investment in unconsolidated affiliates	40.26%
Residential, multi-tenant apartment complex, Units \| item	144

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