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Share-Based Compensation - OP Units Activity (Details) - USD ($) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020
Time-Based OP Units |  |
Number of Units |  |
Beginning balance (in shares) | 93,180 |
Granted (in shares) | 78,335 |
Vested (in shares) | (41,922) |
Forfeited (in shares) | 0 |
Ending balance (in shares) | 129,593 |
Nonvested shares, aggregate intrinsic value | $ 3,800 | $ 3,500
Shares vested, but not released (in shares) | 59,121 |
Shares vested, but not released, aggregate intrinsic value | $ 1,700 |
Total outstanding awards (in shares) | 188,714 |
Total outstanding awards, aggregate intrinsic value | $ 5,500 |
Market-Based OP Units |  |
Number of Units |  |
Beginning balance (in shares) | 178,865 |
Granted (in shares) | 198,007 |
Vested (in shares) | 0 |
Forfeited (in shares) | 0 |
Ending balance (in shares) | 376,872 |
Nonvested shares, aggregate intrinsic value | $ 10,900 | $ 6,700
Shares vested, but not released (in shares) | 0 |
Shares vested, but not released, aggregate intrinsic value | $ 0 |
Total outstanding awards (in shares) | 376,872 |
Total outstanding awards, aggregate intrinsic value | $ 10,900 |

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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + 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)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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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=120381028&loc=d3e5070-113901 + Details
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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=120381028&loc=d3e5070-113901 + Details
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