Summary of PSUs Granted (Detail) - Performance Share Units	12 Months Ended
Dec. 31, 2017 $ / shares shares
Relative 3-year TSR vs NAREIT Apartment Index
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date	Feb. 28, 2017
Type of PSUs Granted	Relative 3-year TSR vs NAREIT Apartment Index
Number of PSUs Granted	135,881
Performance Period Commencement Date	Jan. 01, 2018
Performance Period End Date	Dec. 31, 2020
Grant Date Fair Value \| $ / shares	$ 4.83
Number of PSUs Outstanding as of December 31, 2017	135,881
Absolute 3-Year TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date	Feb. 28, 2017
Type of PSUs Granted	Absolute 3-Year TSR
Number of PSUs Granted	45,294
Performance Period Commencement Date	Jan. 01, 2018
Performance Period End Date	Dec. 31, 2020
Grant Date Fair Value \| $ / shares	$ 3.13
Number of PSUs Outstanding as of December 31, 2017	45,294
Strategic Objectives
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date	Jul. 26, 2017
Type of PSUs Granted	Strategic Objectives
Number of PSUs Granted	45,294
Performance Period Commencement Date	Jan. 01, 2018
Performance Period End Date	Dec. 31, 2020
Grant Date Fair Value \| $ / shares	$ 9.87
Number of PSUs Outstanding as of December 31, 2017	45,294

Share based compensation arrangement by share based payment award equity instruments other than options grant date.

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- Definition

Share based compensation arrangement by share based payment award equity instruments other than options performance period commencement date.

+ References

No definition available.

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- Definition

Share based compensation arrangement by share based payment award equity instruments other than options performance period end date.

+ References

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- Definition

Share based compensation arrangement by share based payment award other than options type of award granted.

+ References

No definition available.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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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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