Segment and Geographic Information - Reconciliation of Total Segment Operating Profit (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Reconciliation to Income Before Income Taxes
Total segment profit from reportable segments	$ 116,296	$ 44,734	$ 42,939	$ 53,390	$ 112,611	$ 71,143	$ 61,358	$ 36,027	$ 257,359	$ 281,139	$ 207,928
General and administrative									(73,035)	(63,231)	(67,181)
Interest income									32,658	28,457	24,954
Interest (expense)									(11,862)	(8,733)	(5,691)
Other (expense) income, net									1,202	664	(838)
Income before income taxes									279,357	301,527	226,353
Operating segments
Reconciliation to Income Before Income Taxes
Total segment profit from reportable segments									330,394	344,370	275,109
Segment reconciling items
Reconciliation to Income Before Income Taxes
General and administrative									(73,035)	(63,231)	(67,181)
Interest income									32,658	28,457	24,954
Interest (expense)									(11,862)	(8,733)	(5,691)
Other (expense) income, net									$ 1,202	$ 664	$ (838)