Securities, Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021
Available-for-sale Debt Securities, Amortized Cost [Abstract]
Within one year	$ 225,666
After one year through five years	8,798
After five years through ten years	25,536
After ten years	1,500
Total available-for-sale debt securities	261,500
Mortgage-backed securities	152,248
Amortized cost	413,748	$ 390,415
Available-for-sale Debt Securities, Fair Value [Abstract]
Within one year	225,805
After one year through five years	8,905
After five years through ten years	25,401
After ten years	1,462
Total available-for-sale debt securities	261,573
Mortgage-backed securities	150,802
Estimated fair value	412,375	390,890
Held-to-maturity Debt Securities, Amortized Cost [Abstract]
Within one year	53,797
After one year through five years	121,956
After five years through ten years	103,780
After ten years	144,807
Total held-to-maturity debt securities	424,340
Mortgage-backed securities	151,558
Amortized cost	575,898	496,914
Held-to-maturity Debt Securities, Fair Value [Abstract]
Within one year	54,546
After one year through five years	126,656
After five years through ten years	108,914
After ten years	149,157
Total held-to-maturity debt securities	439,273
Mortgage-backed securities	155,879
Estimated fair value	595,152	519,042
Total Debt Securities [Abstract]
Amortized cost	989,646	887,329
Estimated fair value	1,007,527	909,932
Securities pledged as collateral for deposits in excess of FDIC insurance limits, fair value	938,500	892,100
Securities pledged as collateral for potential borrowings at the Federal Reserve Bank discount window	$ 3,900	$ 3,900