Securities - Available-for-sale securities, continuous unrealized loss position, Fair value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jun. 30, 2020
Other securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 2,023	$ 995
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	36	5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or more, Fair Value	771	643
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or more, Unrealized Losses	298	338
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,794	1,638
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses	334	343
Mortgage-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	11,656	9,037
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	58	39
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	11,656	9,037
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses	58	39
Total investments and mortgage-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	13,679	10,032
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	94	44
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or more, Fair Value	771	643
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or more, Unrealized Losses	298	338
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	14,450	10,675
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses	$ 392	$ 382