Share-Based Compensation - Variables Used in Black-Scholes Option Pricing Model to Determine Estimated Grant Date Fair Value for Options Granted (Detail) - 2009 Long-Term Incentive Plan [Member] |
12 Months Ended |
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Dec. 31, 2018 | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Expected volatility | 41.00% |
| Weighted-average volatility | 41.00% |
| Expected term (in years) | 6 years 7 months 6 days |
| Risk-free rate | 2.86% |
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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 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 Rate of weighted-average expected volatility for award under share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Details
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