Stock-Based Compensation Plans - Changes in Company's Common Stock Price During Reporting Period (Detail) - Stock Based Compensation Expense [Member] - $ / shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Common stock price at beginning of period | $ 36.06 | $ 24.58 | $ 32.61 | $ 26.72 |
| Common stock price at end of period | 39.01 | 26.36 | 39.01 | 26.36 |
| Increase (decrease) in stock price | $ 2.95 | $ 1.78 | $ 6.40 | $ (0.36) |
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- Definition Increase (decrease) in common stock price. No definition available.
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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 Price of a single share of a number of saleable stocks of a company. No definition available.
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- Details
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