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Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions - Fair Value of Derivatives (Details) | 12 Months Ended
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Dec. 31, 2018 USD ($) item | Dec. 31, 2017 USD ($) item
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Amount to be reclassified as a reduction to interest expense during the next twelve months | $ 24,000 |
Designated |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative liabilities designated as hedging instruments, fair value | $ 58,000 | $ 1,287,000
Designated | Interest Rate Products | OSBC Affiliates |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 1 | 1
Notional Amount | $ 25,774,000 | $ 25,774,000
Derivative liabilities designated as hedging instruments, fair value | 58,000 | 1,287,000
Not designated |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative assets designated as hedging instruments, fair value | 831,000 | 965,000
Derivative liabilities designated as hedging instruments, fair value | $ 698,000 | $ 740,000
Not designated | Interest Rate Products | Commercial Loan Customers |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 25 | 23
Notional Amount | $ 188,931,000 | $ 153,433,000
Derivative assets designated as hedging instruments, fair value | 672,000 | 727,000
Derivative liabilities designated as hedging instruments, fair value | $ 672,000 | $ 727,000
Weighted average maturity | 6 years 7 months 6 days | 6 years 7 months 6 days
Not designated | Interest rate swap agreements net of swap credit valuation |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Cash collateral pledged with financial institutions, dollars | $ 260,000 | $ 0
Investment securities pledged with financial institutions, dollars | $ 0 | $ 4,200,000
Number of correspondent financial institutions where investment securities are pledged | 1 | 1
Not designated | Interest Rate Lock Commitments and Forward Contracts |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 63 | 93
Notional Amount | $ 18,130,000 | $ 26,978,000
Derivative assets designated as hedging instruments, fair value | $ 159,000 | $ 238,000
Not designated | Other Contracts |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 3 | 3
Notional Amount | $ 18,155,000 | $ 15,959,000
Derivative liabilities designated as hedging instruments, fair value | 26,000 | 13,000
Not designated | Forward MBS contracts and forward loan contracts |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Notional Amount | $ 9,315,000 | $ 16,500,000

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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 Represents the number of financial institutions where investment securities are pledged. + References No definition available. + Details
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- Definition Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.1) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),2) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition Fair value of all asset derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959 + Details
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- Definition Fair value of all liability derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959 + Details
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- Definition Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition The number of derivative instruments of a particular group held by the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959 + Details
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- Definition The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994 + Details
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- Definition The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for debt facilities other than FHLB loans, repurchase agreements and letter of credit arrangements, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729 + Details
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