Summary of PSUs Granted (Detail) - Performance Share Units - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Relative 3-year TSR vs NAREIT Apartment Index
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant Date	Feb. 23, 2018	Feb. 28, 2017
Type of PSUs Granted	Relative 3-year TSR vs NAREIT Apartment Index	Relative 3-year TSR vs NAREIT Apartment Index
Number of PSUs Granted	317,906	135,881
Performance Period Commencement Date	Jan. 01, 2018	Jan. 01, 2017
Performance Period End Date	Dec. 31, 2020	Dec. 31, 2019
Grant Date Fair Value	$ 4.19	$ 4.83
Number of PSUs Outstanding as of December 31, 2018	317,906	135,881
Strategic Objectives
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant Date	Feb. 23, 2018	Jul. 26, 2017
Type of PSUs Granted	Strategic Objectives	Strategic Objectives
Number of PSUs Granted	136,245	45,294
Performance Period Commencement Date	Jan. 01, 2018	Jan. 01, 2017
Performance Period End Date	Dec. 31, 2020	Dec. 31, 2019
Grant Date Fair Value	$ 8.67	$ 9.87
Number of PSUs Outstanding as of December 31, 2018	136,245	45,294
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, 2017
Performance Period End Date		Dec. 31, 2019
Grant Date Fair Value		$ 3.13
Number of PSUs Outstanding as of December 31, 2018		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

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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://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&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://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&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://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&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.

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