Investment Securities - Fair Value and Carrying Amount of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Held to maturity, carrying amount, 1 year or less	$ 22,000
Held to maturity, carrying amount, 1 to 5 years	19,002
Held to maturity, carrying amount, 5 to 10 years	34,125
Held to maturity, carrying amount, Mortgage-backed securities and other	188,499
Held to maturity, Amortized Cost	263,626	$ 345,545
Held to maturity, fair value, 1 year or less	22,088
Held to maturity, fair value, 1 to 5 years	18,963
Held to maturity, fair value, 5 to 10 years	31,814
Held to maturity, fair value, Mortgage-backed securities and other	194,839
Held to maturity, fair value, Total	267,704	346,243
Available for sale, amortized cost, 1 year or less	18,007
Available for sale, amortized cost, 1 to 5 years	6,043
Available for sale, amortized cost, Mortgage-backed securities and other	21,819
Available for sale, Amortized Cost	45,869	72,491
Available for sale, fair value, 1 year or less	18,076
Available for sale, fair value, 1 to 5 years	6,039
Available for sale, fair value, Mortgage-backed securities and other	21,877
Available for sale, fair value, Total	$ 45,992	$ 72,228