Securities, Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Available-for-sale Debt Securities, Amortized Cost [Abstract]
Within one year	$ 173,351
After one year through five years	4,181
After five years through ten years	1,544
After ten years	2,000
Total available-for-sale debt securities	181,076
Mortgage-backed securities	43,264
Amortized cost	224,340
Available-for-sale Debt Securities, Fair Value [Abstract]
Within one year	174,383
After one year through five years	4,280
After five years through ten years	1,603
After ten years	2,005
Total available-for-sale debt securities	182,271
Mortgage-backed securities	44,438
Estimated fair value	226,709	$ 122,728
Held-to-maturity Debt Securities, Amortized Cost [Abstract]
Within one year	37,271
After one year through five years	89,352
After five years through ten years	56,560
After ten years	34,008
Total held-to-maturity debt securities	217,191
Mortgage-backed	166,466
Amortized cost	383,657	304,208
Held-to-maturity Debt Securities, Fair Value [Abstract]
Within one year	37,882
After one year through five years	93,517
After five years through ten years	61,606
After ten years	38,395
Total held-to-maturity debt securities	231,400
Mortgage-backed securities	174,112
Estimated fair value	405,512	313,613
Total Debt Securities [Abstract]
Amortized cost	607,997	425,810
Estimated fair value	632,221	436,341
Securities pledged as collateral for deposits in excess of FDIC insurance limits, fair value	619,300	425,700
Securities pledged as collateral for potential borrowings at the Federal Reserve Bank discount window	$ 4,700	$ 1,500