Fair Value Measurements - Estimated fair value of company's financial instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal funds sold	$ 38,987	$ 11,934
Interest bearing deposits with other banks	195,447	303,157
Investment securities available-for-sale, at fair value	843,363	784,139
Loans held for sale	56,707	19,254
Bank owned life insurance	75,724	73,441
Derivative asset	311
Interest bearing deposits	863,856	593,107	$ 420,417
Customer repurchase agreements	30,980	30,413
Derivative liability	611
Interest Rate Swap
Derivative asset		3,727
Derivative liability	203
Interest Rate Caps
Derivative liability	312
Fair Value, Inputs, Level 2 [Member]
Cash and due from banks	7,539	6,773
Federal funds sold	38,987	11,934
Interest bearing deposits with other banks	195,447	303,157
Investment securities available-for-sale, at fair value	832,432	774,345
Federal Reserve and Federal Home Loan Bank stock	35,194	23,506
Loans held for sale	56,707	19,254
Bank owned life insurance	75,724	73,441
Annuity investment	14,697	12,417
Noninterest bearing deposits	2,064,367	2,104,220
Interest bearing deposits	3,876,985	3,542,666
Certificates of deposit	1,291,688	1,325,209
Customer repurchase agreements	30,980	30,413
Borrowings	328,330	218,006
Derivative liability	86
Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swap
Derivative asset		3,727
Derivative liability	203
Fair Value, Inputs, Level 2 [Member] \| Interest Rate Caps
Derivative asset	280
Derivative liability	312
Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale, at fair value	10,931	9,794
Loans, net	7,550,249	6,921,048
Fair Value, Inputs, Level 3 [Member] \| Mortgage Banking Derivative
Derivative asset		229
Derivative liability	66	269
Carrying Value [Member]
Cash and due from banks	7,539	6,773
Federal funds sold	38,987	11,934
Interest bearing deposits with other banks	195,447	303,157
Investment securities available-for-sale, at fair value	843,363	784,139
Federal Reserve and Federal Home Loan Bank stock	35,194	23,506
Loans held for sale	56,707	19,254
Loans, net	7,472,090	6,921,503
Bank owned life insurance	75,724	73,441
Annuity investment	14,697	12,417
Noninterest bearing deposits	2,064,367	2,104,220
Interest bearing deposits	3,876,985	3,542,666
Certificates of deposit	1,283,039	1,327,400
Customer repurchase agreements	30,980	30,413
Borrowings	467,687	217,196
Derivative liability	86
Carrying Value [Member] \| Interest Rate Swap
Derivative asset		3,727
Derivative liability	203
Carrying Value [Member] \| Mortgage Banking Derivative
Derivative asset		229
Derivative liability	66	269
Carrying Value [Member] \| Interest Rate Caps
Derivative asset	280
Derivative liability	312
Fair Value [Member]
Cash and due from banks	7,539	6,773
Federal funds sold	38,987	11,934
Interest bearing deposits with other banks	195,447	303,157
Investment securities available-for-sale, at fair value	843,363	784,139
Federal Reserve and Federal Home Loan Bank stock	35,194	23,506
Loans held for sale	56,707	19,254
Loans, net	7,550,249	6,921,048
Bank owned life insurance	75,724	73,441
Annuity investment	14,697	12,417
Noninterest bearing deposits	2,064,367	2,104,220
Interest bearing deposits	3,876,985	3,542,666
Certificates of deposit	1,291,688	1,325,209
Customer repurchase agreements	30,980	30,413
Borrowings	328,330	218,006
Derivative liability	86
Fair Value [Member] \| Interest Rate Swap
Derivative asset		3,727
Derivative liability	203
Fair Value [Member] \| Mortgage Banking Derivative
Derivative asset		229
Derivative liability	66	$ 269
Fair Value [Member] \| Interest Rate Caps
Derivative asset	280
Derivative liability	$ 312

The aggregate fair value of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

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Fair value amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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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.

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Fair value, after the effects of master netting arrangements, of a financial liability or 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 liabilities not subject to a master netting arrangement and not elected to be offset.

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The amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements.

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The aggregate of all domestic and foreign interest-bearing deposit liabilities.

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Fair value portion of other liabilities.

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The aggregate value of all restricted investments.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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