Segment and Geographic Information - Reconciliation of Total Segment Operating Profit (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Reconciliation to Income Before Income Taxes
Total segment profit from reportable segments	$ 111,223	$ 70,831	$ 63,758	$ 36,990					$ 282,802	$ 209,641	$ 212,016
General and administrative									(63,231)	(56,076)	(51,297)
Interest income									28,457	231	808
Interest (expense)									(8,733)
Other (expense) income, net									664
Income before income taxes									303,190
Operating segments
Reconciliation to Income Before Income Taxes
Total segment profit from reportable segments									346,033
Segment reconciling items
Reconciliation to Income Before Income Taxes
General and administrative									(63,231)
Interest income									28,457
Interest (expense)									(8,733)
Other (expense) income, net									$ 664
Accounting Standards Update 2014-09 (Topic 606) [Member]
Reconciliation to Income Before Income Taxes
Total segment profit from reportable segments					$ 79,784	$ 53,620	$ 30,104	$ 55,714		219,221	216,719
General and administrative										(67,181)	(58,735)
Interest income										24,954	22,942
Interest (expense)										(5,691)	(3,787)
Other (expense) income, net										(838)	1,309
Income before income taxes										237,646	237,183
Accounting Standards Update 2014-09 (Topic 606) [Member] | Operating segments
Reconciliation to Income Before Income Taxes
Total segment profit from reportable segments										286,402	275,454
Accounting Standards Update 2014-09 (Topic 606) [Member] | Segment reconciling items
Reconciliation to Income Before Income Taxes
General and administrative										(67,181)	(58,735)
Interest income										24,954	22,942
Interest (expense)										(5,691)	(3,787)
Other (expense) income, net										$ (838)	$ 1,309