Securities - Schedule of Amortized Cost and Approximate Fair Values, Together with Gross Unrealized Gains and Losses of Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Amortized Cost	$ 134,498	$ 143,506
Available-for-sale Securities, Gross Unrealized Gains	11,817	14,562
Available-for-sale Securities, Gross Unrealized Losses	(2)	(1)
Available-for-sale securities, Fair Value	146,313	158,067
U.S. government agencies
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Amortized Cost	4,000	10,000
Available-for-sale Securities, Gross Unrealized Gains	22	53
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale securities, Fair Value	4,022	10,053
Subordinated notes
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Amortized Cost	4,500	4,500
Available-for-sale Securities, Gross Unrealized Gains	25	6
Available-for-sale Securities, Gross Unrealized Losses	(2)	(1)
Available-for-sale securities, Fair Value	4,523	4,505
State and municipal obligations
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Amortized Cost	125,998	129,006
Available-for-sale Securities, Gross Unrealized Gains	11,770	14,503
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale securities, Fair Value	$ 137,768	$ 143,509

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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