Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Debt securities, amortized cost	$ 146,831	$ 149,954
Equity securities, amortized cost	$ 21,942	$ 16,912
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	9,706,156	9,681,728
Common stock, shares outstanding (in shares)	9,706,156	9,681,728