Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Operating loss carryforwards disclosures
Deferred income taxes	$ (400,000)	$ 16,500,000	$ (61,100,000)
Deferred tax assets, operating loss carryforwards, subject to expiration	292,500,000
Amount of future tax benefits	3,100,000
Increase (decrease) in valuation allowance	400,000
Operating loss carryforward, income tax benefit	0
Unrecognized tax benefits	0	$ 0	$ 0
Undistributed earnings of foreign subsidiaries	61,700,000
Unrecognized tax expense, due to undistributed earnings of foreign subsidiaries not being repatriated	100,000
United Kingdom
Operating loss carryforwards disclosures
Deferred tax assets, operating loss carryforwards, not subject to expiration	4,100,000
Singapore
Operating loss carryforwards disclosures
Deferred tax assets, operating loss carryforwards, not subject to expiration	1,500,000
Operating Loss Carryforward, Expired
Operating loss carryforwards disclosures
Increase (decrease) in valuation allowance	4,000,000.0
Operating Losses, Jurisdictions Without Tax Benefits
Operating loss carryforwards disclosures
Increase (decrease) in valuation allowance	3,600,000
Maximum | United Kingdom
Operating loss carryforwards disclosures
Deferred income taxes	2,300,000
Maximum | Singapore
Operating loss carryforwards disclosures
Deferred income taxes	$ 0.0