Loans and Allowance for Credit Losses - Collateral dependent loans and related ACL (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020
Related allowance for credit losses	$ 32,543	$ 33,222	$ 35,084	$ 25,139
Collateral-dependent Loans | 1- to 4-family residential loans
Amortized cost	889	895
Related allowance for credit losses	217	223
Residential Real Estate
Related allowance for credit losses	10,634	11,192	$ 8,629	$ 4,875
Residential Real Estate | Collateral-dependent Loans
Amortized cost	889	895
Related allowance for credit losses	$ 217	$ 223