Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period - Net of Tax	$ 1,330,971	$ 1,327,193	$ 1,310,421	$ 1,391,530
Retained earnings	1,970,813	2,032,788	1,970,813	2,032,788	$ 1,927,568
Balance at the end of period - Net of Tax	1,313,779	1,294,912	1,313,779	1,294,912
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period - Net of Tax	(8,612)	(176,739)	(9,055)	(137,290)
Balance at the end of period - Net of Tax	(7,711)	(159,118)	(7,711)	(159,118)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period - Net of Tax	(1,065)	(176,883)	(1,383)	(137,389)
Other comprehensive income (loss) - Gross	443	17,624	761	(21,870)
Balance at the end of period - Net of Tax	(622)	(159,259)	(622)	(159,259)
Marketable Securities.
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period - Gross	240	190	242	131
Balance at the beginning of period - Tax	58	46	59	32
Balance at the beginning of period - Net of Tax	182	144	183	99
Other comprehensive income (loss) - Gross	3	(4)	2	55
Other comprehensive income (loss) - Tax	(1)	1	(1)	(13)
Balance at the end of period - Net of Tax	184	141	184	141
Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period - Gross	(10,232)	0	(10,399)	0
Balance at the beginning of period - Tax	(2,503)	0	(2,544)	0
Balance at the beginning of period - Net of Tax	(7,729)	0	(7,855)	0
Other comprehensive income (loss) - Gross	603	0	770	0
Other comprehensive income (loss) - Tax	(147)	0	(188)	0
Balance at the end of period - Net of Tax	$ (7,273)	$ 0	$ (7,273)	$ 0