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Employee Share-Based Incentive Compensation Plans - Restricted Shares (Details) - W T M Incentive Plan - Restricted Stock - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Restricted Shares |  |  |  |
Beginning of period (in shares) | 37,805 | 43,105 | 43,105 | 43,395
Issued (in shares) | 475 | 0 | 13,475 | 14,055
Vested (in shares) | 0 | 0 | (17,717) | (14,345)
Forfeited (in shares) | 0 | 0 | (583) | 0
Expense recognized (in shares) | 0 | 0 | 0 | 0
End of period (in shares) | 38,280 | 43,105 | 38,280 | 43,105
Unamortized Issue Date Fair Value |  |  |  |
Beginning of period | $ 26.2 | $ 26.6 | $ 15.2 | $ 16.7
Issued | 0.5 | 0.0 | 16.1 | 15.1
Vested | 0.0 | 0.0 | 0.0 | 0.0
Forfeited | 0.0 | 0.0 | (0.6) | 0.0
Expense recognized | (3.5) | (3.6) | (7.5) | (8.8)
End of period | $ 23.2 | $ 23.0 | $ 23.2 | $ 23.0

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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + 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 (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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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 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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- Definition Number of shares issued under share-based payment arrangement. + 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 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The total fair value (on the date of issue) for restricted share awards issued during the period. + References No definition available. + Details
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