Share-Based Payments - Summary of Activity for Nonvested Restricted Share Awards (Detail) - Restricted Stock - 2007 and 2017 Omnibus Equity Incentive Plan - $ / shares	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares
Beginning balance, non-vested (in shares)	176,516	94,181	106,458
Granted (in shares)	1,255	126,288	27,282
Vested (in shares)	(85,151)	(40,134)	(38,995)
Forfeited (in shares)	(1,628)	(3,819)	(564)
Ending balance, non-vested (in shares)	90,992	176,516	94,181
Weighted- Average Grant-Date Fair Value
Beginning balance, non-vested (in dollars per share)	$ 31.07	$ 25.42	$ 19.81
Granted (in dollars per share)	31.87	33.04	37.35
Vested (in dollars per share)	29.51	26.69	18.40
Forfeited (in dollars per share)	31.42	31.80	28.66
Ending balance, non-vested (in dollars per share)	$ 32.54	$ 31.07	$ 25.42

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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-Publisher FASB
-Name Accounting Standards Codification
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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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-Publisher FASB
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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