Deposits - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
|
| Deposits [Line Items] | ||
| Time deposits, meet or exceed FDIC insurance limit of $250,000 | $ 100.9 | $ 143.2 |
| Brokered time deposits | $ 30.0 | 67.5 |
| Minimum [Member] | ||
| Deposits [Line Items] | ||
| Brokered time deposits remaining maturities period | 12 months | |
| Maximum [Member] | ||
| Deposits [Line Items] | ||
| Brokered time deposits remaining maturities period | 32 months | |
| PCSB Bank [Member] | ||
| Deposits [Line Items] | ||
| Deposits of local governments | $ 74.4 | $ 44.1 |