Business Combinations - Fair Value Adjustments Made to the Amortized Cost (Details) - USD ($) $ in Thousands		9 Months Ended
	Jul. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Gross amortized cost basis at July 31, 2020	$ 1,787,057
Interest rate fair value adjustment on all loans	455
Credit fair value adjustment on non-PCD loans	(21,397)
Fair value of acquired loans at July 31, 2020	1,766,115
Allowance for credit losses on PCD loans	(13,586)
Loans, net	$ 1,752,529	$ 0	$ 1,752,529