Investment Securities - Available-for-Sale and Held-to-Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Investments [Line Items]
Available-for-sale, amortized cost	$ 83,289	$ 94,071
Available-for-sale, gross unrealized gains	1,855	540
Available-for-sale, gross unrealized losses	(151)	(595)
Investment securities available-for-sale, at fair value	84,993	94,016
Held-to-maturity, amortized cost	6,429	14,340
Held-to-maturity, gross unrealized gains	130	22
Held-to-maturity, gross unrealized losses		(56)
Held-to-maturity, estimated fair value	6,559	14,306
Corporate Note Securities
Schedule Of Investments [Line Items]
Available-for-sale, amortized cost	2,711
Available-for-sale, gross unrealized gains	73
Investment securities available-for-sale, at fair value	2,784
Residential Mortgage Backed Securities [Member]
Schedule Of Investments [Line Items]
Available-for-sale, amortized cost	24,680	46,182
Available-for-sale, gross unrealized gains	865	372
Available-for-sale, gross unrealized losses	(8)	(209)
Investment securities available-for-sale, at fair value	25,537	46,345
Commercial Mortgage Backed Securities [Member]
Schedule Of Investments [Line Items]
Available-for-sale, amortized cost	40,849	43,686
Available-for-sale, gross unrealized gains	780	73
Available-for-sale, gross unrealized losses	(142)	(386)
Investment securities available-for-sale, at fair value	41,487	43,373
Held-to-maturity, amortized cost	4,302	8,923
Held-to-maturity, gross unrealized gains	75	2
Held-to-maturity, gross unrealized losses		(46)
Held-to-maturity, estimated fair value	4,377	8,879
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Investments [Line Items]
Available-for-sale, amortized cost	4,971	4,123
Available-for-sale, gross unrealized gains	137	95
Investment securities available-for-sale, at fair value	5,108	4,218
Held-to-maturity, amortized cost	1,007	1,093
Held-to-maturity, gross unrealized gains	21	15
Held-to-maturity, estimated fair value	1,028	1,108
US Treasury Securities [Member]
Schedule Of Investments [Line Items]
Available-for-sale, amortized cost	10,078	80
Available-for-sale, gross unrealized losses	(1)
Investment securities available-for-sale, at fair value	10,077	80
US Government Agencies Debt Securities [Member]
Schedule Of Investments [Line Items]
Held-to-maturity, amortized cost	1,120	4,324
Held-to-maturity, gross unrealized gains	34	5
Held-to-maturity, gross unrealized losses		(10)
Held-to-maturity, estimated fair value	$ 1,154	$ 4,319

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) 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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