Share based compensation arrangement by share based payment award fair value grant period.

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- Definition

TSR Restricted Shares Performance Measurement Period

+ References

No definition available.

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- Definition

Weighted Percentage of Index Used to Compare to TSR

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No definition available.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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.

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- Definition

Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

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- Definition

Number of options outstanding, including both vested and non-vested options.

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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- Definition

Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Share-Based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unvested compensation cost not yet recognized for options and restricted stock awards	$ 9.9
Weighted average period over which unvested compensation cost expected to be recognized	1 year 7 months 6 days
Grant period	10 years
Employee Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Term of stock options	10 years
Requisite service period	4 years
Stock option outstanding	827,853
Stock options outstanding, aggregate intrinsic value	$ 3.1
Stock options outstanding, weighted average remaining contractual term	4 years 9 months 18 days
Stock options exercisable	733,942
Stock options exercisable, aggregate intrinsic value	$ 2.9
Stock options exercisable, weighted average remaining contractual term	4 years 10 months 24 days
TSR Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
TSR restricted shares performance measurement period	3 years
Term of stock options	10 years
Options granted, weighted average grant-date fair value (dollars per share)	$ 8.15
TSR Stock Awards [Member] \| NAREIT Apartment Index [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	60.00%
TSR Stock Awards [Member] \| MSCI US REIT Index [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	40.00%
TSR LTIP Units [Member] \| 36 Months After Grant Date [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
TSR LTIP Units [Member] \| 48 Months After Grant Date [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
Time-Based Restricted Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Requisite service period	4 years
Number of share unvested	94,663
Weighted average grant fair value	$ 45.51
Aggregate fair value of restricted stock awards that vested	$ 7.5	$ 13.7	$ 8.4
TSR Restricted Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share unvested	222,848
Weighted average grant fair value	$ 49.43
TSR LTIP II Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share unvested	1,112,342
Weighted average grant fair value	$ 9.58
2020 Stock Award and Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available to be granted under plan (in shares)	3,000,000