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Loans and Related Allowance for Loan and Lease Losses - Impaired Loans by Class (Detail) - USD ($) $ in Thousands | Sep. 30, 2016 | Dec. 31, 2015 | Dec. 31, 2014
--- | --- | --- | ---
Recorded investment, with no related allowance | $ 5,802 | $ 7,472 | $ 10,119
Unpaid principal balance, with no related allowance | 5,796 | 7,460 | 10,107
Recorded investment, with related allowance | 5,844 | 6,209 | 4,249
Unpaid principal balance, with related allowance | 5,832 | 6,193 | 4,246
Related allowance | 544 | 833 | 1,596
Recorded investment | 11,646 | 13,681 | 14,368
Unpaid principal balance | 11,628 | 13,653 | 14,353
Scenario, Previously Reported [Member] |  |  |
Recorded investment, with no related allowance |  | 7,466 |
Unpaid principal balance, with no related allowance |  | 7,454 |
Recorded investment, with related allowance |  | 6,215 |
Unpaid principal balance, with related allowance |  | 6,199 |
Commercial And Industrial [Member] |  |  |
Recorded investment, with no related allowance | 569 | 1,027 | 1,146
Unpaid principal balance, with no related allowance | 569 | 1,025 | 1,145
Recorded investment, with related allowance | 275 | 781 | 247
Unpaid principal balance, with related allowance | 275 | 781 | 247
Related allowance | 184 | 388 | 83
Recorded investment | 844 | 1,808 | 1,393
Unpaid principal balance | 844 | 1,806 | 1,392
Real Estate Construction Porfolio Segment [Member] |  |  |
Recorded investment, with no related allowance | 1,076 | 1,657 | 2,707
Unpaid principal balance, with no related allowance | 1,076 | 1,651 | 2,705
Recorded investment, with related allowance | 17 | 130 | 589
Unpaid principal balance, with related allowance | 17 | 130 | 589
Related allowance | 17 | 130 | 589
Recorded investment | 1,093 | 1,787 | 3,296
Unpaid principal balance | 1,093 | 1,781 | 3,294
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |  |
Recorded investment, with no related allowance | 2,774 | 2,445 | 2,202
Unpaid principal balance, with no related allowance | 2,771 | 2,443 | 2,197
Recorded investment, with related allowance | 464 | 1,436 | 2,981
Unpaid principal balance, with related allowance | 462 | 1,436 | 2,978
Related allowance | 104 | 276 | 892
Recorded investment | 3,238 | 3,881 | 5,183
Unpaid principal balance | 3,233 | 3,879 | 5,175
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member] |  |  |
Recorded investment, with no related allowance | 1,378 | 2,337 | 4,064
Unpaid principal balance, with no related allowance | 1,375 | 2,335 | 4,060
Recorded investment, with related allowance | 5,088 | 3,862 | 426
Unpaid principal balance, with related allowance | 5,078 | 3,846 | 426
Related allowance | 239 | 39 | 30
Recorded investment | 6,466 | 6,199 | 4,490
Unpaid principal balance | 6,453 | 6,181 | 4,486
Consumer Portfolio Segment [Member] |  |  |
Recorded investment, with no related allowance | 5 | 6 |
Unpaid principal balance, with no related allowance | 5 | 6 |
Recorded investment, with related allowance |  | 6 | 6
Unpaid principal balance, with related allowance |  | 6 | 6
Related allowance |  |  | 2
Recorded investment | 5 | 6 | 6
Unpaid principal balance | $ 5 | $ 6 | $ 6

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- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953550-111524 + Details
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