Employee Benefit Plans - Schedule of Activity for the Restricted Stock Component of the Plan (Detail) - Restricted Stock [Member]	12 Months Ended
Dec. 31, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Beginning Balance \| shares	263,457
Restricted Stock, Granted \| shares	161,503
Restricted Stock, Vested \| shares	(75,646)
Restricted Stock, Forfeited \| shares	(5,123)
Restricted Stock, Dividend reinvestment \| shares	8,059
Restricted Stock Ending Balance \| shares	352,250
Weighted Average Grant Date Fair Value Per Share Beginning Balance \| $ / shares	$ 40.21
Weighted Average Grant Date Fair Value Per Share, Granted \| $ / shares	38.51
Weighted Average Grant Date Fair Value Per Share, Vested \| $ / shares	34.13
Weighted Average Grant Date Fair Value Per Share, Forfeited \| $ / shares	35.33
Weighted Average Grant Date Fair Value Per Share, Dividend reinvestment \| $ / shares	37.82
Weighted Average Grant Date Fair Value Per Share Ending Balance \| $ / shares	$ 40.75

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)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(3)
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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
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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).

+ References

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-Publisher FASB
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-Topic 718
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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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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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.

+ References

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-Publisher FASB
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-Topic 718
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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.

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No definition available.

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Share based compensation arrangement by share based payment award equity instruments other than options dividend reinvestment in period.

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Share based compensation arrangement by share based payment award equity instruments other than options dividend reinvestment weighted average grant date fair value.

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