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Income Taxes (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2016 | Sep. 30, 2015 | Dec. 31, 2015
Operating Loss Carryforwards [Line Items] |  |  |  |  |
Income tax provision | $ 30,783 | $ 25,720 | $ 82,663 | $ 74,672 |
Effective income tax rates | 38.10% | 38.00% | 37.80% | 37.90% |
Actual income tax rates | 37.20% | 38.10% | 36.70% | 38.00% |
Unrecognized tax benefits, reduction resulting from lapse of applicable statute of limitations | $ 800 |  |  |  |
Excess tax benefit from share-based compensation, tax provision |  |  | $ 2,100 |  |
Unrecognized income tax benefits | 3,900 |  | 3,900 |  | $ 4,800
Unrecognized income tax benefits, if recognized, that would favorably affect the effective income tax rate | 2,200 |  | 2,200 |  | 3,000
Accrued interest expense related to unrecognized income tax benefits | 400 |  | 400 |  | $ 400
Interest income related to unrecognized income tax benefits | 100 |  | 100 |  |
Interest expense related to unrecognized income tax benefits |  | $ 100 |  | $ 100 |
Unrecognized income tax benefits to be recognized in the next twelve months | $ 3,300 |  | $ 3,300 |  |

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