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Loans and Related Allowance for Loan and Lease Losses - Primary Segments of the Loan Portfolio (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Individually evaluated for impairment	$ 11,646	$ 13,681	$ 14,368
Collectively evaluated for impairment	574,683	520,029	456,216
Total loans	586,329	533,710	470,584
Commercial And Industrial [Member]
Individually evaluated for impairment	844	1,808	1,393
Collectively evaluated for impairment	58,532	40,728	33,535
Total loans	59,376	42,536	34,928
Real Estate Construction Porfolio Segment [Member]
Individually evaluated for impairment	1,093	1,787	3,296
Collectively evaluated for impairment	16,540	20,350	27,000
Total loans	17,633	22,137	30,296
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Individually evaluated for impairment	3,238	3,881	5,183
Collectively evaluated for impairment	255,714	228,597	204,913
Total loans	258,952	232,478	210,096
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Individually evaluated for impairment	6,466	6,199	4,490
Collectively evaluated for impairment	239,170	225,502	186,195
Total loans	245,636	231,701	190,685
Consumer Portfolio Segment [Member]
Individually evaluated for impairment	5	6	6
Collectively evaluated for impairment	4,727	4,852	4,573
Total loans	$ 4,732	$ 4,858	$ 4,579

X

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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X

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

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