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Stock-Based Compensation, Stock Award and Incentive Plan and Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Employee service share-based compensation, aggregate disclosures [Abstract] |  |  |
Increase in number of shares available for issuance (in shares) | 1,300,000 |  |
Term of stock options granted under Plan | 10 years |  |
Share based compensation costs | $ 10.2 | $ 8.1 | $ 6.2
Minimum [Member] |  |  |
Employee service share-based compensation, aggregate disclosures [Abstract] |  |  |
Vesting period | 1 year |  |
Maximum [Member] |  |  |
Employee service share-based compensation, aggregate disclosures [Abstract] |  |  |
Percentage of shares not subject to minimum vesting requirement | 5.00% |  |
Stock Options [Member] |  |  |
Employee service share-based compensation, aggregate disclosures [Abstract] |  |  |
Vesting period | 3 years |  |
Share based compensation costs | $ 4.6 | 4.8 | 4.2
Tax benefit of share-based compensation | $ 1.2 | $ 1.3 | $ 1.1
Forfeiture rate assumed | 8.45% | 8.85% | 8.20%
Weighted average grant date fair value for stock options granted (in dollars per share) | $ 18.99 | $ 18.86 | $ 25.79
Weighted average grant date fair value for stock options vested (in dollars per share) | $ 23.85 | $ 22.46 | $ 21.33
Total intrinsic value of stock options exercised | $ 2.3 | $ 2.2 | $ 3.3
Weighted Average Assumptions [Abstract] |  |  |
Expected life | 6 years 8 months 12 days | 6 years 7 months 6 days | 6 years 2 months 12 days
Interest rate | 1.67% | 2.62% | 2.50%
Volatility | 30.34% | 30.26% | 30.33%
Expected dividend yield | 0.35% | 0.37% | 0.26%
Stock Options [Roll Forward] |  |  |
Balance, beginning of year (in shares) | 1,227,620 |  |
Granted (in shares) | 286,078 |  |
Exercised (in shares) | (93,099) |  |
Canceled (in shares) | (57,233) |  |
Balance, end of year (in shares) | 1,363,366 | 1,227,620 |
Exercisable, end of year (in shares) | 876,206 |  |
Weighted Average Exercise Price Per Share [Abstract] |  |  |
Balance, beginning of year (in dollars per share) | $ 55.83 |  |
Granted (in dollars per share) | 57.67 |  |
Exercised (in dollars per share) | 35.11 |  |
Canceled (in dollars per share) | 63.92 |  |
Balance, end of year (in dollars per share) | 57.29 | $ 55.83 |
Exercisable, end of year (in dollars per share) | $ 56.55 |  |
Weighted Average Remaining Contractual Life [Abstract] |  |  |
Outstanding options, end of year | 6 years 1 month 24 days |  |
Exercisable options, end of year | 4 years 9 months 29 days |  |
Aggregate Intrinsic Value [Abstract] |  |  |
Outstanding options, end of year | $ 11.4 |  |
Exercisable options, end of year | $ 8.9 |  |
Additional Information [Abstract] |  |  |
Closing stock price on last business day of the period (in dollars per share) | $ 62.12 |  |
Weighted average intrinsic value of options exercised (in dollars per share) | $ 24.41 | $ 27.21 | $ 33.10
Unrecognized stock-based compensation expense | $ 4.7 |  |
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized | 3 years |  |
Nonvested Stock Options [Member] |  |  |
Stock Options [Roll Forward] |  |  |
Balance, beginning of year (in shares) | 438,773 |  |
Granted (in shares) | 286,078 |  |
Vested (in shares) | (199,723) |  |
Canceled (in shares) | (37,968) |  |
Balance, end of year (in shares) | 487,160 | 438,773 |
Weighted Average Exercise Price Per Share [Abstract] |  |  |
Balance, beginning of year (in dollars per share) | $ 63.15 |  |
Granted (in dollars per share) | 57.67 |  |
Vested (in dollars per share) | 66.94 |  |
Canceled (in dollars per share) | 60.15 |  |
Balance, end of year (in dollars per share) | $ 58.61 | $ 63.15 |

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