Commitments and Contingencies - Commitments and Letters of Credit (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Commitments and letters of credit	$ 2,750,554	$ 2,777,942
Commitments to extend credit
Other Commitments [Line Items]
Commitments and letters of credit	2,697,493	2,713,586
Standby letters of credit
Other Commitments [Line Items]
Commitments and letters of credit	$ 53,061	$ 64,356