aggregate fair value and gross unrealized loss of securities that have been in a continuous unrealized loss position (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Aggregate Fair Value Gross Unrealized Loss Of Securities Less Than 12 Months Fair Value [Member]
Available-for-sale
U.S. Treasury	$ 10,302
U.S. Government Agency notes	20,550	$ 2,553
Municipal bonds	13,980	558
U.S. Government agencies and U.S. Government - sponsored enterprises	42,471	3,761
Collateralized mortgage obligations	4,625
Corporate bonds
Total temporarily impaired securities	91,928	6,872
Aggregate Fair Value Gross Unrealized Loss Of Securities Less Than 12 Months Unrealized Losses [Member]
Available-for-sale
U.S. Treasury	95
U.S. Government Agency notes	80	36
Municipal bonds	251	1
U.S. Government agencies and U.S. Government - sponsored enterprises	647	42
Collateralized mortgage obligations	66
Corporate bonds
Total temporarily impaired securities	1,139	79
Aggregate Fair Value Gross Unrealized Loss Of Securities 12 Months Or Longer Fair Value [Member]
Available-for-sale
U.S. Treasury
U.S. Government Agency notes	1,125	20
Municipal bonds
U.S. Government agencies and U.S. Government - sponsored enterprises	1,398	45
Collateralized mortgage obligations
Corporate bonds
Total temporarily impaired securities	2,523	65
Aggregate Fair Value Gross Unrealized Loss Of Securities 12 Months Or Longer Unrealized Losses [Member]
Available-for-sale
U.S. Treasury
U.S. Government Agency notes	19	1
Municipal bonds
U.S. Government agencies and U.S. Government - sponsored enterprises	26	1
Collateralized mortgage obligations
Corporate bonds
Total temporarily impaired securities	45	2
Aggregate Fair Value Gross Unrealized Loss Of Securities Total Fair Value [Member]
Available-for-sale
U.S. Treasury	10,302
U.S. Government Agency notes	21,675	2,573
Municipal bonds	13,980	558
U.S. Government agencies and U.S. Government - sponsored enterprises	43,869	3,806
Collateralized mortgage obligations	4,625
Corporate bonds
Total temporarily impaired securities	94,451	6,937
Aggregate Fair Value Gross Unrealized Loss Of Securities Total Unrealized Losses [Member]
Available-for-sale
U.S. Treasury	95
U.S. Government Agency notes	99	37
Municipal bonds	251	1
U.S. Government agencies and U.S. Government - sponsored enterprises	698	43
Collateralized mortgage obligations	41
Corporate bonds
Total temporarily impaired securities	$ 1,184	$ 81