Investment Securities - Investments with Unrealized Loss Positions for total investment securities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Investment Securities
Unrealized Holding Losses Less Than 12 Months, Fair Value	$ 63,630	$ 12,928
Unrealized Holding Losses Less Than 12 Months, Unrealized Losses	151	52
Unrealized Holding Losses 12 Months or More, Fair Value	2,026	2,040
Unrealized Holding Losses 12 Months or More, Unrealized Losses	18	17
Unrealized Holding Losses Total, Fair Value	65,656	14,968
Unrealized Holding Losses Total, Unrealized Losses	$ 169	$ 69