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Income Taxes (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |  |  |
Effective Income Tax Rate, Percent | 25.90% | 39.40% | 18.40% | 32.80% |
Valuation Allowance [Abstract] |  |  |  |  |
Valuation Allowance, Amount | $ 0 |  | $ 0 |  | $ 0
Income Tax Uncertainties [Abstract] |  |  |  |  |
Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 3,400 |  | 3,400 |  | 4,800
Unrecognized Tax Benefits, Period Increase (Decrease) | 300 | $ (100) | (1,600) | $ (2,900) |
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued | 900 |  | 900 |  | $ 2,300
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense | 100 | $ (0) | (1,400) | $ (1,300) |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |  |  |  |
Balance beginning of period |  |  | 5,839 |  |
Additions based on tax positions related to current year |  |  | 394 |  |
Additions for tax positions of prior years |  |  | 0 |  |
Reductions for tax positions of prior years |  |  | 0 |  |
Reductions due to lapse of applicable statute of limitations |  |  | (1,954) |  |
Settlements |  |  | 0 |  |
Balance end of period | 4,279 |  | 4,279 |  |
Maximum [Member] |  |  |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound | (800) |  | (800) |  |
Minimum [Member] |  |  |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound | $ (200) |  | $ (200) |  |

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