amortized cost, fair value and tax equivalent yield of securities, by maturity (Details) $ in Thousands	6 Months Ended
Jun. 30, 2021 USD ($)
U S Government Agency Notes 1 [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 3,497
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 3,502
Receivable with Imputed Interest, Effective Yield (Interest Rate)	2.77%
U S Government Agency Notes 2 [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 15,917
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 15,931
Receivable with Imputed Interest, Effective Yield (Interest Rate)	1.30%
U S Government Agency Notes Total [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 19,414
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 19,433
Receivable with Imputed Interest, Effective Yield (Interest Rate)	1.56%
U S States And Political Subdivisions 2 [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 3,030
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 3,210
Receivable with Imputed Interest, Effective Yield (Interest Rate)	2.71%
U S States And Political Subdivisions 3 [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 26,455
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 27,869
Receivable with Imputed Interest, Effective Yield (Interest Rate)	2.85%
U S States And Political Subdivisions Total [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 29,485
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 31,079
Receivable with Imputed Interest, Effective Yield (Interest Rate)	2.84%
US Government Agencies Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 88,775
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 89,805
Receivable with Imputed Interest, Effective Yield (Interest Rate)	1.73%
Corporate Debt Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 10,000
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 10,213
Receivable with Imputed Interest, Effective Yield (Interest Rate)	4.88%
Available-for-sale Securities [Member]
Open Option Contracts Written [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	$ 147,674
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 150,530
Receivable with Imputed Interest, Effective Yield (Interest Rate)	2.14%

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date.

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