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Fair Value of Assets and Liabilities, Part II (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017
Foreclosed Assets Held for Sale [Abstract] |  |  |
Other real estate owned |  | $ 1,951,000 | $ 2,754,000
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Assets, Fair Value Disclosure, Recurring |  | 2,522,000 | 2,548,000
Financial Assets [Abstract] |  |  |
Available-for-sale securities |  | 569,862,000 | 578,579,000
Held-to-maturity Securities |  | 69,358,000 | 69,332,000
Held-to-maturity Securities, Fair Value |  | 67,631,000 | 68,457,000
Financial Liabilities [Abstract] |  |  |
Other borrowings |  | 9,375,000 | 10,313,000
Carrying Amount [Member] |  |  |
Financial Assets [Abstract] |  |  |
Cash and due from banks |  | 54,344,000 | 88,388,000
Federal funds sold |  | 491,000 | 491,000
Certificates of deposit investments |  | 1,685,000 | 1,685,000
Available-for-sale securities |  | 569,862,000 | 578,579,000
Held-to-maturity Securities |  | 69,358,000 | 69,332,000
Loans held for sale |  | 1,309,000 | 1,025,000
Loans net of allowance for loan losses |  | 1,955,617,000 | 1,918,499,000
Interest receivable |  | 10,182,000 | 10,832,000
Federal Reserve Bank stock |  | 5,160,000 | 5,160,000
Federal Home Loan Bank stock |  | 2,407,000 | 2,407,000
Financial Liabilities [Abstract] |  |  |
Deposits |  | 2,291,891,000 | 2,274,639,000
Securities sold under agreements to repurchase |  | 132,435,000 | 155,388,000
Interest payable |  | 709,000 | 602,000
Federal Home Loan Bank borrowings |  | 60,024,000 | 60,038,000
Other Liabilities, Fair Value Disclosure |  |  | 10,313,000
Other borrowings |  | 9,375,000 |
Junior subordinated debentures |  | 24,021,000 | 24,000,000
Fair Value [Member] |  |  |
Financial Assets [Abstract] |  |  |
Cash and due from banks |  | 54,344,000 | 88,388,000
Federal funds sold |  | 491,000 | 491,000
Certificates of deposit investments |  | 1,682,000 | 1,692,000
Available-for-sale securities |  | 569,862,000 | 578,579,000
Held-to-maturity Securities, Fair Value |  | 67,631,000 | 68,457,000
Loans held for sale |  | 1,309,000 | 1,025,000
Loans net of allowance for loan losses |  | 1,887,726,000 | 1,899,678,000
Interest receivable |  | 10,182,000 | 10,832,000
Federal Reserve Bank stock |  | 5,160,000 | 5,160,000
Federal Home Loan Bank stock |  | 2,407,000 | 2,407,000
Financial Liabilities [Abstract] |  |  |
Deposits |  | 2,287,907,000 | 2,272,868,000
Securities sold under agreements to repurchase |  | 132,420,000 | 155,394,000
Interest payable |  | 709,000 | 602,000
Federal Home Loan Bank borrowings |  | 59,599,000 | 59,968,000
Other Liabilities, Fair Value Disclosure |  |  | 10,313,000
Other borrowings |  | 9,375,000 |
Junior subordinated debentures |  | 18,899,000 | 18,050,000
Fair Value, Measurements, Nonrecurring [Member] | Carrying Amount [Member] |  |  |
Foreclosed Assets Held for Sale [Abstract] |  |  |
Other real estate owned |  | 1,951,000 |
Fair Value, Measurements, Nonrecurring [Member] | Fair Value [Member] |  |  |
Foreclosed Assets Held for Sale [Abstract] |  |  |
Other real estate owned |  | 24,000 |
Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Financial Assets [Abstract] |  |  |
Cash and due from banks |  | 54,344,000 | 88,388,000
Federal funds sold |  | 491,000 | 491,000
Certificates of deposit investments |  | 0 | 0
Available-for-sale securities |  | 192,000 | 172,000
Held-to-maturity Securities, Fair Value |  | 0 | 0
Loans held for sale |  | 0 | 0
Loans net of allowance for loan losses |  | 0 | 0
Interest receivable |  | 0 | 0
Federal Reserve Bank stock |  | 0 | 0
Federal Home Loan Bank stock |  | 0 | 0
Financial Liabilities [Abstract] |  |  |
Deposits |  | 0 | 0
Securities sold under agreements to repurchase |  | 0 | 0
Interest payable |  | 0 | 0
Federal Home Loan Bank borrowings |  | 0 | 0
Other borrowings |  | 0 | 0
Junior subordinated debentures |  | 0 | 0
Significant Other Observable Inputs (Level 2) |  |  |
Financial Assets [Abstract] |  |  |
Cash and due from banks |  | 0 | 0
Federal funds sold |  | 0 | 0
Certificates of deposit investments |  | 1,682,000 | 1,692,000
Available-for-sale securities |  | 567,148,000 | 575,859,000
Held-to-maturity Securities, Fair Value |  | 67,631,000 | 68,457,000
Loans held for sale |  | 1,309,000 | 1,025,000
Loans net of allowance for loan losses |  | 0 | 0
Interest receivable |  | 10,182,000 | 10,832,000
Federal Reserve Bank stock |  | 5,160,000 | 5,160,000
Federal Home Loan Bank stock |  | 2,407,000 | 2,407,000
Financial Liabilities [Abstract] |  |  |
Deposits |  | 1,949,676,000 | 1,930,604,000
Securities sold under agreements to repurchase |  | 132,420,000 | 155,394,000
Interest payable |  | 709,000 | 602,000
Federal Home Loan Bank borrowings |  | 59,599,000 | 59,968,000
Other borrowings |  | 9,375,000 | 10,313,000
Junior subordinated debentures |  | 18,899,000 | 18,050,000
Significant Unobservable Inputs (Level 3) |  |  |
Financial Assets [Abstract] |  |  |
Cash and due from banks |  | 0 | 0
Federal funds sold |  | 0 | 0
Certificates of deposit investments |  | 0 | 0
Available-for-sale securities |  | 2,522,000 | 2,548,000
Held-to-maturity Securities, Fair Value |  | 0 | 0
Loans held for sale |  | 0 | 0
Loans net of allowance for loan losses |  | 1,887,726,000 | 1,899,678,000
Interest receivable |  | 0 | 0
Federal Reserve Bank stock |  | 0 | 0
Federal Home Loan Bank stock |  | 0 | 0
Financial Liabilities [Abstract] |  |  |
Deposits |  | 338,231,000 | 342,264,000
Securities sold under agreements to repurchase |  | 0 | 0
Interest payable |  | 0 | 0
Federal Home Loan Bank borrowings |  | 0 | 0
Other borrowings |  | 0 | 0
Junior subordinated debentures |  | $ 0 | $ 0
Trust preferred securities | Significant Unobservable Inputs (Level 3) | Discounted Cash Flow [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount rate (in hundredths) |  | 11.70% | 12.70%
Constant prepayment rate (in hundredths) | [1] | 1.50% | 1.30%
Cumulative projected prepayments (in hundredths) |  | 23.90% | 21.60%
Probability of default (in hundredths) |  | 0.50% | 0.50%
Loss severity (in hundredths) |  | 97.80% | 97.70%
Projected cures given deferral (in hundredths) |  | 0.00% | 0.00%
Impaired loans (collateral dependent) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | $ 3,489,000 | $ 3,053,000
Impaired loans (collateral dependent) | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | 0 | 0
Impaired loans (collateral dependent) | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | $ 0 | $ 0
Impaired loans (collateral dependent) | Significant Unobservable Inputs (Level 3) | Minimum [Member] | Third Party Valuations [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount to reflect realizable value |  | 0.00% | 0.00%
Impaired loans (collateral dependent) | Significant Unobservable Inputs (Level 3) | Maximum [Member] | Third Party Valuations [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount to reflect realizable value |  | 40.00% | 40.00%
Impaired loans (collateral dependent) | Significant Unobservable Inputs (Level 3) | Weighted Average [Member] | Third Party Valuations [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount to reflect realizable value |  | 20.00% | 20.00%
Impaired loans (collateral dependent) | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | $ 3,489,000 | $ 3,053,000
Assets Held-for-sale [Member] | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | 24,000 | 91,000
Assets Held-for-sale [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | 0 | 0
Assets Held-for-sale [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | $ 0 | $ 0
Assets Held-for-sale [Member] | Significant Unobservable Inputs (Level 3) | Minimum [Member] | Third Party Valuations [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount to reflect realizable value less estimated selling costs (in hundredths) |  | 0.00% | 0.00%
Assets Held-for-sale [Member] | Significant Unobservable Inputs (Level 3) | Maximum [Member] | Third Party Valuations [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount to reflect realizable value less estimated selling costs (in hundredths) |  | 40.00% | 40.00%
Assets Held-for-sale [Member] | Significant Unobservable Inputs (Level 3) | Weighted Average [Member] | Third Party Valuations [Member] |  |  |
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract] |  |  |
Discount to reflect realizable value less estimated selling costs (in hundredths) |  | 35.00% | 35.00%
Assets Held-for-sale [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring [Member] |  |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |  |
Assets, Fair Value Disclosure, Nonrecurring |  | $ 24,000 | $ 91,000
[1] | Every five years

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- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. + References No definition available. + Details
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- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This element represents the fair value of interest payable. + References No definition available. + Details
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- Definition Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=SL6742756-110258 + Details
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562 + Details
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- Definition Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13476-108611 + Details
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- Definition Fair value portion of federal funds sold and securities borrowed or purchased under agreements to resell. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13(3)(a)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.6) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Fair value of investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
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- Definition Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 325 -SubTopic 20 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=29638263&loc=d3e39828-111592 + Details
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