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Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Additional disclosures [Abstract] |  |  |
Stock-based compensation expense | $ 4,210 | $ 3,936 | $ 3,644
Number of shares available for future grant (in shares) | 988,494 |  |
Stock Options [Member] |  |  |
Share-based compensation [Abstract] |  |  |
Stock awards termination period | 10 years |  |
Stock options [Roll Forward] |  |  |
Outstanding, beginning of period (in shares) | 66,900 |  |
Exercised (in shares) | (32,505) |  |
Expired (in shares) | (1,250) |  |
Outstanding, end of period (in shares) | 33,145 | 66,900 |
Exercisable, end of period (in shares) | 33,145 |  |
Stock options, weighted average exercise price [Abstract] |  |  |
Outstanding, beginning of period (in dollars per share) | $ 23.07 |  |
Exercised (in dollars per share) | 22.31 |  |
Expired (in dollars per share) | 25.38 |  |
Outstanding, end of period (in dollars per share) | 23.73 | $ 23.07 |
Exercisable, end of period (in dollars per share) | $ 23.73 |  |
Additional disclosures [Abstract] |  |  |
Weighted average remaining contractual term, outstanding, end of period | 1 year 10 months 9 days |  |
Weighted average remaining contractual term, exercisable, end of period | 1 year 10 months 9 days |  |
Aggregate intrinsic value, outstanding, end of period | $ 558,066 |  |
Aggregate intrinsic value, exercisable, end of period | 558,066 |  |
Stock-based compensation expense | 1 | $ 11 | 18
Proceeds from stock options exercised | 725 | 999 | 3,083
Tax benefits related to stock options exercised | 123 | 173 | 650
Intrinsic value of stock options exercised | 490 | 692 | 1,699
Fair value of shares vested during the year | 13 | 16 | 329
Restricted Stock [Member] |  |  |
Additional disclosures [Abstract] |  |  |
Stock-based compensation expense | $ 4,200 | $ 3,900 | 3,500
Restricted Stock [Member] | Employees [Member] | Minimum [Member] |  |  |
Share-based compensation [Abstract] |  |  |
Stock awards vesting period | 3 years |  |
Restricted Stock [Member] | Employees [Member] | Maximum [Member] |  |  |
Share-based compensation [Abstract] |  |  |
Stock awards vesting period | 5 years |  |
Restricted Stock [Member] | Non-employee Directors [Member] |  |  |
Share-based compensation [Abstract] |  |  |
Stock awards vesting period | 3 years |  |
Restricted Stock Units (RSUs) [Member] |  |  |
Restricted stock and restricted stock units [Roll Forward] |  |  |
Unvested, beginning of period (in shares) | 546,054 |  |
Forfeited (in shares) | (10,886) |  |
Vested (in shares) | (121,774) |  |
Granted (in shares) | 142,046 |  |
Unvested, end of period (in shares) | 555,440 | 546,054 |
Restricted stock and restricted stock units, weighted average grant date fair value [Abstract] |  |  |
Unvested, beginning of period (in dollars per share) | $ 28.39 |  |
Forfeited (in dollars per share) | 31.06 |  |
Vested (in dollars per share) | 25.66 |  |
Granted (in dollars per share) | 33.04 |  |
Unvested, end of period (in dollars per share) | $ 30.11 | $ 28.39 |
Restricted Stock Awards and Stock Units [Member] |  |  |
Additional disclosures [Abstract] |  |  |
Tax benefit on restricted stock awards | $ 1,100 | $ 1,200 | $ 2,500
Unrecognized compensation cost | $ 5,500 |  |
Unrecognized compensation cost, weighted average period of recognition | 1 year 9 months 18 days |  |

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