Quarterly Information - Quarterly Net Income, Basic Earnings Per Share and Diluted Earnings Per Share (Parenthetical) (Detail) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended |
|---|---|---|
Dec. 31, 2014 |
Dec. 31, 2014 |
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| Quarterly Financial Information Disclosure [Abstract] | ||
| Increased in operating income by pre-tax amount | $ 16.6 | |
| Increase in net income, net of tax | $ 12.0 |
| X | ||||||||||
- Definition Increase decrease in operating income. No definition available.
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| X | ||||||||||
- Definition Increase in net income net of tax. No definition available.
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| X | ||||||||||
- References No definition available.
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