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Employee Share-Based Incentive Compensation Plans - Narrative (Details) $ in Millions | 12 Months Ended | 36 Months Ended |
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Dec. 31, 2022 USD ($) multiplier shares | Dec. 31, 2021 USD ($) shares | Dec. 31, 2020 USD ($) shares | Dec. 31, 2021 USD ($) shares | Dec. 31, 2019 USD ($)
Performance Shares |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Vesting period | 3 years |  |  |  |
Multiplier for determining payout, low end of range | multiplier | 0 |  |  |  |
Multiplier for determining payout, high end of range | multiplier | 2 |  |  |  |
Performance cycle period | 3 years |  |  |  |
New grants (in shares) | 13,225 | 13,475 | 14,055 |  |
Unamortized grant date fair value | $ | $ 36.7 |  |  |  |
Performance Shares | 2020 – 2022 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Targeted performance goal (as a percent) | 7.00% |  |  |  |
Payout for maximum growth target percentage | 200.00% |  |  |  |
Performance Shares | 2021 – 2023 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Targeted performance goal (as a percent) | 8.00% |  |  |  |
Payout for maximum growth target percentage | 200.00% |  |  |  |
Performance Shares | 2022 – 2024 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Targeted performance goal (as a percent) | 9.00% |  |  |  |
Payout for maximum growth target percentage | 200.00% |  |  |  |
Performance Shares | Minimum | 2020 – 2022 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Payout for minimum growth target percentage | 2.00% |  |  |  |
Performance Shares | Minimum | 2021 – 2023 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Payout for minimum growth target percentage | 3.00% |  |  |  |
Performance Shares | Minimum | 2022 – 2024 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Payout for minimum growth target percentage | 4.00% |  |  |  |
Performance Shares | Maximum | 2020 – 2022 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Payout for minimum growth target percentage | 12.00% |  |  |  |
Performance Shares | Maximum | 2021 – 2023 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Payout for minimum growth target percentage | 13.00% |  |  |  |
Performance Shares | Maximum | 2022 – 2024 |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Payout for minimum growth target percentage | 14.00% |  |  |  |
Performance Shares | W T M Incentive Plan |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
New grants (in shares) |  |  |  | 750 |
Restricted Stock |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Vesting period | 34 months |  |  |  |
Unamortized grant date fair value | $ | $ 15.5 | $ 15.9 | $ 15.2 | $ 15.9 | $ 16.7
Shares issued (in shares) | 13,225 | 13,475 | 14,055 |  |
Restricted Share Cliff Vesting in January 2024 | W T M Incentive and Phantom Plan |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Shares issued (in shares) | 13,225 |  |  |  |
Restricted Share Cliff Vesting in January 2023 | W T M Incentive and Phantom Plan |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Shares issued (in shares) |  | 13,475 |  |  |
Restricted Share Cliff Vesting in January 2022 | W T M Incentive and Phantom Plan |  |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |  |
Shares issued (in shares) |  |  | 14,055 |  |

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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/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(01) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + Details
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