Fair Value Measurements and Disclosures - Financial assets measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value Measurements and Disclosures
Securities available for sale	$ 52,757	$ 50,428
Mortgage loans held-for-investment	11,278	11,422
State and municipal securities
Fair Value Measurements and Disclosures
Securities available for sale	8,882	10,919
Investments in mutual funds and other equity securities
Fair Value Measurements and Disclosures
Securities available for sale	1,014	979
Interest rate lock commitments
Fair Value Measurements and Disclosures
Derivative assets, Fair value	283
Recurring
Fair Value Measurements and Disclosures
Mortgage loans held-for-sale	48,615	37,695
Mortgage loans held-for-investment	11,278	11,422
Mortgage servicing rights	314	213
SBA loan servicing rights	321
Total	114,068	100,209
Recurring \| U.S. government agency mortgage-backed securities
Fair Value Measurements and Disclosures
Securities available for sale	12,900	23,866
Recurring \| U.S. government agency collateralized mortgage obligations
Fair Value Measurements and Disclosures
Securities available for sale	29,961	14,664
Recurring \| State and municipal securities
Fair Value Measurements and Disclosures
Securities available for sale		10,919
Recurring \| Investments in mutual funds and other equity securities
Fair Value Measurements and Disclosures
Securities available for sale	9,896	979
Recurring \| Interest rate lock commitments
Fair Value Measurements and Disclosures
Derivative assets, Fair value	283	310
Recurring \| Customer derivatives - Interest rate swaps
Fair Value Measurements and Disclosures
Derivative assets, Fair value	500	141
Recurring \| Level 2
Fair Value Measurements and Disclosures
Mortgage loans held-for-sale	48,615	37,695
Mortgage loans held-for-investment	11,278	11,422
Total	113,150	99,686
Recurring \| Level 2 \| U.S. government agency mortgage-backed securities
Fair Value Measurements and Disclosures
Securities available for sale	12,900	23,866
Recurring \| Level 2 \| U.S. government agency collateralized mortgage obligations
Fair Value Measurements and Disclosures
Securities available for sale	29,961	14,664
Recurring \| Level 2 \| State and municipal securities
Fair Value Measurements and Disclosures
Securities available for sale		10,919
Recurring \| Level 2 \| Investments in mutual funds and other equity securities
Fair Value Measurements and Disclosures
Securities available for sale	9,896	979
Recurring \| Level 2 \| Customer derivatives - Interest rate swaps
Fair Value Measurements and Disclosures
Derivative assets, Fair value	500	141
Recurring \| Level 3
Fair Value Measurements and Disclosures
Mortgage servicing rights	314	213
SBA loan servicing rights	321
Total	918	523
Recurring \| Level 3 \| Interest rate lock commitments
Fair Value Measurements and Disclosures
Derivative assets, Fair value	$ 283	$ 310

Fair value portion of mortgage servicing rights.

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Fair value portion of mortgage loans held-for-investment.

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Fair value portion of SBA servicing rights.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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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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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 portion of mortgage loans held-for-sale.

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