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Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Detail) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2015 USD ($) | Sep. 30, 2016 USD ($) | Sep. 30, 2015 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Commercial And Industrial [Member] |  |  |  |  |  |
Number of contracts | 2 | 2 | 4 | 6 |  | 7
Pre-modification outstanding recorded investment | $ 15 | $ 169 | $ 126 | $ 434 |  | $ 1,264
Post-modification outstanding recorded investment | $ 15 | $ 169 | $ 126 | $ 434 |  | $ 1,264
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |  |  |  |  |
Number of contracts | 1 | 1 | 3 | 6 | 3 | 7
Pre-modification outstanding recorded investment | $ 164 | $ 58 | $ 398 | $ 515 | $ 140 | $ 784
Post-modification outstanding recorded investment | $ 164 | $ 58 | $ 418 | $ 535 | $ 140 | $ 784
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member] |  |  |  |  |  |
Number of contracts |  | 1 |  | 1 | 1 | 2
Pre-modification outstanding recorded investment |  | $ 311 |  | $ 270 | $ 48 | $ 834
Post-modification outstanding recorded investment |  | $ 311 |  | $ 270 | $ 48 | $ 834
Consumer Portfolio Segment [Member] |  |  |  |  |  |
Number of contracts | 1 |  | 1 |  | 1 |
Pre-modification outstanding recorded investment | $ 9 |  | $ 9 |  | $ 6 |
Post-modification outstanding recorded investment | $ 9 |  | $ 9 |  | $ 6 |
Real Estate Construction Porfolio Segment [Member] |  |  |  |  |  |
Number of contracts |  |  | 1 | 1 |  |
Pre-modification outstanding recorded investment |  |  | $ 181 | $ 181 |  |
Post-modification outstanding recorded investment |  |  | $ 181 | $ 181 |  |
Extended Maturity [Member] | Commercial And Industrial [Member] |  |  |  |  |  |
Number of contracts | 2 | 2 | 3 | 6 |  | 6
Extended Maturity [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |  |  |  |  |
Number of contracts | 1 | 1 | 2 | 5 | 3 | 7
Extended Maturity [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member] |  |  |  |  |  |
Number of contracts |  | 1 |  | 1 | 1 | 2
Extended Maturity [Member] | Consumer Portfolio Segment [Member] |  |  |  |  |  |
Number of contracts | 1 |  | 1 |  | 1 |
Extended Maturity [Member] | Real Estate Construction Porfolio Segment [Member] |  |  |  |  |  |
Number of contracts |  |  | 1 | 1 |  |
Other Restructurings [Member] | Commercial And Industrial [Member] |  |  |  |  |  |
Number of contracts |  |  | 1 |  |  | 1
Other Restructurings [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |  |  |  |  |
Number of contracts |  |  | 1 | 1 |  |
Other Restructurings [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member] |  |  |  |  |  |
Number of contracts |  |  |  |  |  |
Other Restructurings [Member] | Consumer Portfolio Segment [Member] |  |  |  |  |  |
Number of contracts |  |  |  |  |  |
Other Restructurings [Member] | Real Estate Construction Porfolio Segment [Member] |  |  |  |  |  |
Number of contracts |  |  |  |  |  |

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- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524 + Details
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- Definition Post-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524 + Details
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