Troubled Debt Restructuring (Detail) Number in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018 USD ($) Number	Sep. 30, 2017 USD ($) Number	Sep. 30, 2018 USD ($) Number	Sep. 30, 2017 USD ($) Number
Financing Receivable, Modifications [Line Items]
Total Modification	$ 0		$ 0
Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Number	0	2	0	2
Pre- Modification Outstanding Recorded Investment	$ 0	$ 40	$ 0	$ 40
Post-Modification Outstanding Recorded Investment	0	40	0	40
Interest Only	0	0	0	0
Term	0	40	0	40
Combination	0	0	0	0
Total Modification	$ 0	$ 40	$ 0	$ 40
Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Number	0	1	0	3
Pre- Modification Outstanding Recorded Investment	$ 0	$ 62	$ 0	$ 189
Post-Modification Outstanding Recorded Investment	0	62	0	165
Interest Only	0	0	0	0
Term	0	62	0	165
Combination	0	0	0	0
Total Modification	$ 0	$ 62	$ 0	$ 62
Residential real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Number	0	0	0	0
Pre- Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post-Modification Outstanding Recorded Investment	0	0	0	0
Interest Only	0	0	0	0
Term	0	0	0	0
Combination	0	0	0	0
Total Modification	$ 0	$ 0	$ 0	$ 0
Installment
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Number	0	0	0	0
Pre- Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post-Modification Outstanding Recorded Investment	0	0	0	0
Consumer
Financing Receivable, Modifications [Line Items]
Interest Only	0	0	0	0
Term	0	0	0	0
Combination	0	0	0	0
Total Modification	$ 0	$ 0	$ 0	$ 0

Financing receivable, modifications combination

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- Definition

Financing receivable modifications interest only

+ References

No definition available.

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- Definition

Financing receivable, modifications term

+ References

No definition available.

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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.

+ References

No definition available.

+ Details

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18845-111554

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