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Share-Based Compensation (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended | 36 Months Ended |
--- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | May 12, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Common stock available for awards, shares |  |  |  |  |  |  | 10,000,000
Common stock reserved for future awards, shares | 10,007,832 |  |  |  |  | 10,007,832 |
Stock-based employee compensation expense | $ 13.5 | $ 16.3 | $ 15.2 |  |  |  |
Related tax benefits | 3.3 | 4.0 | 3.7 |  |  |  |
Excess Tax Benefit from Share-based Compensation, Operating Activities |  | 0.8 | 1.0 |  |  |  |
Unrecognized compensation cost related to nonvested awards | $ 19.1 |  |  |  |  | $ 19.1 |
Weighted-average remaining requisite service period, years | 1 year 10 months 24 days |  |  |  |  |  |
RTSR Modifier | 25.00% |  |  |  |  |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay | 3.00% |  |  |  |  |  |
401(k) match, profit sharing and non-elective expense | $ 37.8 | $ 37.5 | $ 37.6 |  |  |  |
Excess Tax Expense - Share Based Compensation | $ 0.4 |  |  |  |  |  |
Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares granted | 235,100 |  |  |  |  |  |
Shares nonvested | 478,227 | 302,606 |  |  |  | 478,227 |
Shares vesting period, (years) |  |  |  |  |  | 3 years |
Performance Shares |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares granted | 528,729 | 552,389 | 514,338 |  |  |  |
Shares nonvested | 1,384,336 | 1,503,251 |  |  |  | 1,384,336 |
Performance Shares | NOEPS |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Fair value of shares granted | $ 11.7 | $ 11.7 | $ 9.2 |  |  |  |
Performance Shares | CVI |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Fair value of shares granted | $ 2.6 | $ 2.5 | $ 2.4 |  |  |  |
Omnibus Plan | Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Units issued | 210,273 |  |  |  |  |  |
Director Plan | Non-Employee Director Award |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 67,806 |  |  |  |  | 67,806 |
2018 Award | Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares granted |  |  | 158,689 |  |  |  |
Fair value of shares granted |  |  | $ 3.5 |  |  |  |
Shares nonvested | 119,333 |  |  |  |  | 119,333 |
2018 Award | Performance Shares | NOEPS |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 347,479 |  |  |  |  | 347,479 |
2018 Award | Performance Shares | CVI |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 80,185 |  |  |  |  | 80,185 |
2019 Award | Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares granted |  | 166,031 |  |  |  |  |
Fair value of shares granted |  | $ 4.1 |  |  |  |  |
Shares nonvested | 135,170 |  |  |  |  | 135,170 |
2019 Award | Performance Shares | NOEPS |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 384,680 |  |  |  |  | 384,680 |
2019 Award | Performance Shares | CVI |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 88,769 |  |  |  |  | 88,769 |
2020 award | Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares granted | 235,100 |  |  |  |  |  |
Fair value of shares granted | $ 6.1 |  |  |  |  |  |
Shares nonvested | 223,724 |  |  |  |  | 223,724 |
2020 award | Performance Shares | NOEPS |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 392,619 |  |  |  |  | 392,619 |
2020 award | Performance Shares | CVI |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares nonvested | 90,604 |  |  |  |  | 90,604 |
Subsequent Event | Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares vesting period, (years) |  |  |  | 3 years | 3 years |  |
Subsequent Event | Performance Shares |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares vesting period, (years) |  |  |  |  | 3 years |  |

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