Defined Contribution Plans (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Jun. 30, 2018	Jun. 30, 2017
Retirement Benefits [Abstract]
Employer matching contribution (as percent)		100.00%
Employer matching contribution, percent of employee's pay (as percent)		5.00%
Aggregate company contributions to its benefit plans	$ 0.1	$ 1.9	$ 0.1	$ 0.1