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Income Taxes (Tables) | 9 Months Ended
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Sep. 30, 2019
Income Tax Disclosure [Abstract] |
Schedule of Income Tax Expense and Effective Tax Rate | The following table presents the income tax expense and the effective tax rate for the three and nine months ended September 30, 2019 and 2018:
($ in thousands) |  | Three Months Ended September 30, |  | Nine Months Ended September 30,
| 2019 |  | 2018 |  | % Change |  | 2019 |  | 2018 |  | % Change
Income before income taxes |  | $ | 206,367 |  |  | $ | 204,865 |  |  | 1 | % |  | $ | 624,635 |  |  | $ | 613,641 |  |  | 2 | %
Income tax expense |  | $ | 34,951 |  |  | $ | 33,563 |  |  | 4 | % |  | $ | 138,815 |  |  | $ | 82,958 |  |  | 67 | %
Effective tax rate |  | 16.9 | % |  | 16.4 | % |  |  |  |  | 22.2 | % |  | 13.5 | % |  |  |

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