Short-Term Borrowings - Summary of Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Total	$ 500	$ 500
Weighted average interest rate	0.38%	0.15%
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Total	$ 500	$ 500
Short-term Debt [Member]
Short-term Debt [Line Items]
End of period interest rate	0.63%	0.38%

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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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Period Type:	duration

- Definition

Weighted average interest rate of short-term debt outstanding.

+ References

+ Details

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Data Type:	num:percentItemType
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Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_ExtinguishmentOfDebtAxis=us-gaap_ShortTermDebtMember
Namespace Prefix:
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