Investment Securities - Carrying value of other investment securities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Other investment securities
Carrying Value	$ 160,592	$ 160,443
Impairment on other investment securities	0
Federal Home Loan Bank stock
Other investment securities
Carrying Value	16,283	15,083
Federal Reserve Bank Stock
Other investment securities
Carrying Value	129,716	129,871
Investment in unconsolidated subsidiaries
Other investment securities
Carrying Value	3,563	4,941
Other nonmarketable investment securities
Other investment securities
Carrying Value	$ 11,030	$ 10,548