| Stock-Based Compensation - Assumptions Long-Term Awards (Details) shares in Thousands | 6 Months Ended | 
|---|---|
| Jun. 30, 2019  $ / shares  shares | |
| Target awards | shares | 110 | 
| 2019 Long-Term Awards | |
| Adoption date price | $ / shares | $ 10.07 | 
| Target awards | shares | 82 | 
| Volatility | 31.70% | 
| Risk-free rate | 2.50% | 
| Dividend assumption | reinvested | 
| Expected term in years | 3 years | 
| 2018 Program [Member] | |
| Adoption date price | $ / shares | $ 8.86 | 
| Volatility | 33.80% | 
| Risk-free rate | 2.60% | 
| Dividend assumption | reinvested | 
| Expected term in years | 2 years 8 months 12 days | 
| 2017 Program [Member] | |
| Adoption date price | $ / shares | $ 8.86 | 
| Target awards | shares | 96 | 
| Dividend assumption | reinvested | 
| 2017 Program [Member] | Maximum [Member] | |
| Volatility | 35.40% | 
| Risk-free rate | 2.60% | 
| Expected term in years | 2 years 8 months 12 days | 
| 2017 Program [Member] | Minimum [Member] | |
| Volatility | 33.80% | 
| Risk-free rate | 2.40% | 
| Expected term in years | 1 year 8 months 12 days | 
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition If different dividend rates are used during the contractual term, then disclose the range of expected dividends used. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition The number of shares purchased on the open market during the period for issuance to employees under the plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Price of a single share of a number of saleable stocks of a company. No definition available. 
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- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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