aggregate fair value and gross unrealized loss of securities that have been in a continuous unrealized loss position (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Aggregate Fair Value Gross Unrealized Loss Of Securities Less Than 12 Months Fair Value [Member]
Available-for-sale
U.S. Government Agency notes	$ 10,993	$ 2,553
Municipal bonds	4,996	558
U.S. Government agencies and U.S. Government - sponsored enterprises	36,534	3,761
U.S. Government agencies	4,030
Total temporarily impaired securities	56,553	6,872
Aggregate Fair Value Gross Unrealized Loss Of Securities Less Than 12 Months Unrealized Losses [Member]
Available-for-sale
U.S. Government Agency notes	86	36
Municipal bonds	74	1
U.S. Government agencies and U.S. Government - sponsored enterprises	499	42
U.S. Government agencies	62
Total temporarily impaired securities	721	79
Aggregate Fair Value Gross Unrealized Loss Of Securities 12 Months Or Longer Fair Value [Member]
Available-for-sale
U.S. Government Agency notes		20
Municipal bonds
U.S. Government agencies and U.S. Government - sponsored enterprises		45
U.S. Government agencies
Total temporarily impaired securities		65
Aggregate Fair Value Gross Unrealized Loss Of Securities 12 Months Or Longer Unrealized Losses [Member]
Available-for-sale
U.S. Government Agency notes		1
Municipal bonds
U.S. Government agencies and U.S. Government - sponsored enterprises		1
U.S. Government agencies
Total temporarily impaired securities		2
Aggregate Fair Value Gross Unrealized Loss Of Securities Total Fair Value [Member]
Available-for-sale
U.S. Government Agency notes	10,993	2,573
Municipal bonds	4,996	558
U.S. Government agencies and U.S. Government - sponsored enterprises	36,534	3,806
U.S. Government agencies	4,030
Total temporarily impaired securities	56,553	6,937
Aggregate Fair Value Gross Unrealized Loss Of Securities Total Unrealized Losses [Member]
Available-for-sale
U.S. Government Agency notes	86	37
Municipal bonds	74	1
U.S. Government agencies and U.S. Government - sponsored enterprises	499	43
U.S. Government agencies	62
Total temporarily impaired securities	$ 721	$ 81