Funds Held for Customers - Additional Information (Details) - USD ($)	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019
Funds Held For Customers [Line Items]
Amortized Cost	$ 678,895,000	$ 626,740,000
Fair value	$ 679,835,000	$ 628,784,000
Debt securities percentage mature within one year	100.00%	100.00%
Short term marketable debt realized gains or losses	$ 0		$ 0
Accrued Interest Receivable
Funds Held For Customers [Line Items]
Amortized Cost	1,800,000	$ 2,900,000
Fair value	$ 1,800,000	$ 2,900,000