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Derivatives - Narrative (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2017 USD ($) | Dec. 31, 2018 USD ($) derivative_swap | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Derivatives, Fair Value [Line Items] |  |  |  |
Threshold for collateral requirements |  | $ 250,000 |  |
Collateral posted |  | 296,000 | $ 300,000 |
Notional amount |  | $ 16,000,000 | 12,500,000 |
Number of instruments | derivative_swap |  | 6 |  |
Derivative fee income |  | $ 84,000 | 26,000 | $ 0
Commitments to originate loans held for sale |  | 44,999,000 | 43,602,000 |
RML |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Commitments to originate loans held for sale |  | 45,000,000 | 43,600,000 |
Variable to Fixed |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Notional amount |  | $ 8,000,000 |  |
Number of instruments | derivative_swap |  | 3 |  |
Fixed to Variable |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Notional amount |  | $ 8,000,000 |  |
Number of instruments | derivative_swap |  | 3 |  |
Interest rate swaps | Designated as Hedging Instrument |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Cash pledged to collateralize fair value exposure on interest rate swap |  | $ 400,000 | 400,000 |
Unrealized gain on interest rate swap |  | $ 607,000 | $ 184,000 |
Subordinated Debt |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Junior subordinated debenture | $ 10,000,000 |  |  |
Effective interest rate on junior subordinated debenture | 3.72% |  |  |
Debt instrument, interest rate during period |  | 4.16% |  |
Subordinated Debt | LIBOR |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Debt instrument, basis spread on variable rate | 1.37% |  |  |

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition Derivatives, Value Shortfalls Threshold Triggering Additional Collateral Requirements + References No definition available. + Details
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- Definition Accumulated adjustment, net of tax, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains or losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450520&loc=d3e32583-110901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669686-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e681-108580 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=109240241&loc=d3e32022-110900 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580 + Details
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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959 + Details
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- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
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- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41678-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
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