Fair Values of Financial Instruments - Assets measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Available for sale debt securities:
Available for sale debt securities, at fair value	$ 343,558	$ 308,657
Equity securities
Equity securities	4,396	4,976
U.S. Treasury and Agency securities
Available for sale debt securities:
Available for sale debt securities, at fair value	168,437	122,168
U.S. Treasury and Agency securities | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	168,437	122,168
U.S. Treasury and Agency securities | Level 1 | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	116,355	48,827
U.S. Treasury and Agency securities | Level 2 | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	52,082	73,341
Mortgage-backed securities
Available for sale debt securities:
Available for sale debt securities, at fair value	36,733	49,437
Mortgage-backed securities | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	36,733	49,437
Mortgage-backed securities | Level 2 | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	36,733	49,437
Collateralized mortgage obligations
Available for sale debt securities:
Available for sale debt securities, at fair value	138,241	136,849
Collateralized mortgage obligations | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	138,241	136,849
Collateralized mortgage obligations | Level 2 | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	138,241	136,849
Collateralized debt obligations
Available for sale debt securities:
Available for sale debt securities, at fair value	147	203
Collateralized debt obligations | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	147	203
Collateralized debt obligations | Level 3 | Recurring
Available for sale debt securities:
Available for sale debt securities, at fair value	147	203
Equity securities | Recurring
Equity securities
Equity securities	4,396	4,976
Equity securities | Level 1 | Recurring
Equity securities
Equity securities	$ 4,396	$ 4,976