v3.8.0.1

Credit Risk Concentrations - Additional Information (Detail) - customer	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Concentration Risk [Line Items]
Number of tenants or common franchises	0	0	0
Operating Expenses | Management Contracts Concentration Risk
Concentration Risk [Line Items]
Concentrations risk percentage	20.00%	25.00%	27.00%
Mortgages and Notes Payable | Credit Availability Concentration Risk | Financial Institution One
Concentration Risk [Line Items]
Concentrations risk percentage	27.00%	20.00%	22.00%
Mortgages and Notes Payable | Credit Availability Concentration Risk | Financial Institution Two
Concentration Risk [Line Items]
Concentrations risk percentage	17.00%	18.00%	13.00%
Mortgages and Notes Payable | Credit Availability Concentration Risk | Financial Institution Three
Concentration Risk [Line Items]
Concentrations risk percentage	13.00%	12.00%	13.00%
Mortgages and Notes Payable | Credit Availability Concentration Risk | Financial Institution Four
Concentration Risk [Line Items]
Concentrations risk percentage	11.00%	11.00%	11.00%
Mortgages and Notes Payable | Credit Availability Concentration Risk | Financial Institution Five
Concentration Risk [Line Items]
Concentrations risk percentage			10.00%

X

- Definition

Number of major customer.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611

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