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Derivative Instruments and Hedging Activities - Value of Derivative Assets and Derivative Liabilities (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
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Derivatives not Designated as Hedging Instruments |  |
Fair value, Derivatives (included in Other Assets) | $ 6,960 | $ 11,295
Fair value, Derivatives (included in Other Liabilities) | 6,958 | 11,276
Collateral posted, Derivatives (included in Other Liabilities) | 14,340 | 12,573
Other Assets | Interest Rate Swap Contracts-Commercial Loans |  |
Derivatives not Designated as Hedging Instruments |  |
Fair value, Derivatives (included in Other Assets) | 6,960 | 11,295
Notional amount, Derivatives (included in Other Assets) | 232,396 | 245,595
Other Assets | Interest Rate Lock Commitments-Mortgage Loans |  |
Derivatives not Designated as Hedging Instruments |  |
Fair value, Derivatives (included in Other Assets) | 236 | 261
Notional amount, Derivatives (included in Other Assets) | 8,490 | 9,894
Other Assets | Forward Sale Contracts-Mortgage Loans |  |
Derivatives not Designated as Hedging Instruments |  |
Fair value, Derivatives (included in Other Assets) | 0 | 0
Notional amount, Derivatives (included in Other Assets) | 0 | 0
Other Liabilities | Interest Rate Swap Contracts-Commercial Loans |  |
Derivatives not Designated as Hedging Instruments |  |
Fair value, Derivatives (included in Other Liabilities) | 6,958 | 11,276
Notional amount, Derivatives (included in Other Liabilities) | 232,396 | 245,595
Collateral posted, Derivatives (included in Other Liabilities) | 14,340 | 12,753
Other Liabilities | Forward Sale Contracts-Mortgage Loans |  |
Derivatives not Designated as Hedging Instruments |  |
Fair value, Derivatives (included in Other Liabilities) | 27 | 5
Notional amount, Derivatives (included in Other Liabilities) | $ 8,216 | $ 9,800

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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13495-108611 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226008-175313 + Details
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