Earnings per Share - Reconciliation of Shares Outstanding for Basic and Diluted Earnings per Share (Detail) - shares shares in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Weighted average shares issued net of Treasury shares	32,500	22,861	32,410	20,083
Less: Unallocated ESOP shares	(315)	(349)	(319)	(353)
Unallocated incentive award shares and shares held by deferred compensation plan	(63)	(34)	(77)	(36)
Average basic shares outstanding	32,122	22,478	32,014	19,694
Add: Effect of dilutive securities:
Stock options	999	382	1,080	282
Shares held by deferred compensation plan	17	20	17	20
Average diluted shares outstanding	33,138	22,880	33,111	19,996

Unallocated Incentive Award Shares And Shares Held By Deferred Compensation Plan

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- Definition

Number of shares issued pursuant to the terms of a deferred compensation arrangement.

+ References

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-Publisher FASB
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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

+ References

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-Publisher FASB
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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

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- Definition

Number of employee stock ownership plan (ESOP) shares that have not been committed to be released determined by relating the portion of time within a reporting period that these shares have been outstanding to the total time in that period.

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- Definition

This element represents the weighted average total number of shares issued throughout the period including the first (beginning balance outstanding) and last (ending balance outstanding) day of the period before considering any reductions (for instance, shares held in treasury) to arrive at the weighted average number of shares outstanding. Weighted average relates to the portion of time within a reporting period that common shares have been issued and outstanding to the total time in that period. Such concept is used in determining the weighted average number of shares outstanding for purposes of calculating earnings per share (basic).

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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