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Stockholders' Equity (Details) |  | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
Oct. 22, 2018 $ / shares | Sep. 30, 2018 USD ($) shares | Mar. 31, 2018 USD ($) | Sep. 30, 2018 USD ($) $ / shares shares | Sep. 30, 2017 USD ($) $ / shares shares | Apr. 20, 2018 USD ($)
Class of Stock [Line Items] |  |  |  |  |  |
Shares withheld for tax withholding and exercise of options (in shares) | shares |  |  |  | 20,981 | 11,938 |
Amount of shares withheld for tax withholding and exercise of options |  |  |  | $ 1,500,000 | $ 782,000 |
Shares withheld for tax withholding and exercise of options, weighted average price (usd per share) | $ / shares |  |  |  | $ 71.35 | $ 65.50 |
Reclassification from AOCI to retained earnings for stranded income tax effects |  |  |  | $ 0 |  |
Share Repurchase Program, amount approved to repurchase |  |  |  |  |  | $ 25,000,000.0
Stock repurchased, net of commissions |  | $ 1,435,000 |  | $ 1,539,000 |  |
Performance-based stock awards |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Vesting period of performance-based stock awards |  |  |  | 3 years |  |
Performance-based stock awards | Minimum |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Vesting percentage of performance-based awards |  |  |  | 0.00% |  |
Performance-based stock awards | Maximum |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Vesting percentage of performance-based awards |  |  |  | 200.00% |  |
Retained Earnings |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Reclassification from AOCI to retained earnings for stranded income tax effects |  |  | $ 638,000 | $ 638,000 |  |
Common Stock |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Stock repurchased, net of commissions (in shares) | shares |  | 16,545 |  | 17,943 |  |
Stock repurchased, net of commissions |  | $ 1,435,000 |  | $ 1,539,000 |  |
Subsequent Event |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Dividends declared per common share (usd per share) | $ / shares | $ 0.35 |  |  |  |  |
Stock split, conversion ratio | 2 |  |  |  |  |

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