Securities, Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Available-for-sale Debt Securities, Amortized Cost [Abstract]
Within one year	$ 185,344
After one year through five years	4,180
After five years through ten years	1,544
After ten years	1,500
Total available for sale debt securities	192,568
Mortgage-backed securities	74,990
Amortized cost	267,558
Available-for-sale Debt Securities, Fair Value [Abstract]
Within one year	186,139
After one through five years	4,275
After five through ten years	1,609
After ten years	1,459
Total available-for-sale debt securities	193,482
Mortgage-backed securities	76,188
Estimated fair value	269,670	$ 226,709
Held-to-maturity Debt Securities, Amortized Cost [Abstract]
Within one year	39,303
After one year through five years	93,973
After five years through ten years	61,550
After ten years	41,726
Total held-to-maturity debt securities	236,552
Mortgage-backed securities	153,555
Amortized cost	390,107	383,657
Held-to-maturity Debt Securities, Fair Value [Abstract]
Within one year	39,964
After one year through five years	98,398
After five years through ten years	66,780
After ten years	46,458
Total held-to-maturity debt securities	251,600
Mortgage-backed securities	161,966
Estimated fair value	413,566	405,512
Total Debt Securities [Abstract]
Amortized cost	657,665	607,997
Estimated fair value	683,236	632,221
Securities pledged as collateral for deposits in excess of FDIC insurance limits, fair value	667,200	619,300
Securities pledged as collateral for potential borrowings at the Federal Reserve Bank discount window	$ 4,100	$ 4,700