Earnings Per Share - Schedule of Computations of Weighted Average Shares Outstanding (Parenthetical) (Detail) - shares shares in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2018
Share Based Awards [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Potentially dilutive restricted share awards excluded from computation of diluted EPS	0.3	0.7

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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