Dispositions - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2015 USD ($) a	Dec. 31, 2014 USD ($) ft²
Dispositions
Property sold	$ 1,424	$ 625
Gain on sale of real estate	470	$ 69
ASSETS
Total Assets	1,721
LIABILITIES
Total Liabilities	659
Operating Partnership \| Fargo, North Dakota
Dispositions
Property sold	1,424
Gain on sale of real estate	$ 470
Development Land Two, Fargo, ND \| Operating Partnership \| Fargo, North Dakota
Dispositions
Area of land \| a	3.38
Office Property, Norfolk, Nebraska \| Operating Partnership \| Norfolk, Nebraska
Dispositions
Area of commercial property \| ft²		14,736
Property sold		$ 625
Gain on sale of real estate		$ 69
Medical Property, Eau Claire, Wisconsin
ASSETS
Real estate investments	$ 1,716
Receivables	5
Total Assets	1,721
LIABILITIES
Mortgage notes payable	655
Accrued expenses and other liabilities	4
Total Liabilities	$ 659

Amount classified as mortgage notes payable attributable to disposal group held for sale or disposed of.

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Amount classified as real estate investments attributable to disposal group held for sale or disposed of.

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Area of land held.

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Area of a real estate property.

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Amount classified as assets attributable to disposal group held for sale or disposed of.

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Amount classified as accounts, notes and loans receivable attributable to disposal group held for sale or disposed of.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

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Amount classified as accrued liabilities attributable to disposal group held for sale or disposed of.

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The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.14(d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 14
-Subparagraph d
-Article 9

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-Name Accounting Standards Codification
-Topic 205
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759

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Cash received from the sale of real estate that is held for investment, that is, it is part of an investing activity during the period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 12
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