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Loans (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | $ 6,584,773 | $ 6,198,057
Deferred loan origination costs, net | 42,600 | 40,300
Residential loans held for sale | 700 | 600
Loans serviced for unrelated third parties | 586,700 | 604,000
Mortgage servicing rights | 600 | 900
Loans and Leases Receivable, Related Parties [Roll Forward] |  |
Balance at January 1 | 2,050 | 2,346
New loans | 297 | 936
Adjustment due to change in composition of related parties | 198 | (406)
Repayments | (968) | (826)
Balance at December 31 | 1,577 | 2,050
Commercial [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | 1,317,174 | 1,242,701
Commercial Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | 1,711,095 | 1,543,301
Consumer [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | 1,740,038 | 1,641,657
Home Equity [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | 494,771 | 507,784
Residential Real Estate Mortgages [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | 1,321,695 | 1,262,614
Commercial Loans [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | 3,028,269 | 2,786,002
Commercial Loans [Member] | Agricultural and Agricultural Real Estate Mortgages [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans serviced for unrelated third parties | 29,100 | 28,500
Consumer Loans [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Net Loans | $ 2,234,809 | $ 2,149,441

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- Definition Reflects the sum for the period of the additions and reductions to related party loans for the change in status of related party classification for individuals with loans. + References No definition available. + Details
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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=82891408&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=84173941&loc=d3e5074-111524 + Details
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