Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Common Stock [Member] Cumulative Effect Of Change In Accounting Standards [Member]	Common Stock [Member]	Additional Paid-In Capital [Member] Cumulative Effect Of Change In Accounting Standards [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member] Cumulative Effect Of Change In Accounting Standards [Member]	Treasury Stock [Member]	Retained Earnings [Member] Cumulative Effect Of Change In Accounting Standards [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Cumulative Effect Of Change In Accounting Standards [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Cumulative Effect Of Change In Accounting Standards [Member]	Total
Beginning balance at Jun. 30, 2018		$ 571		$ 1,450,821		$ (1,600,412)		$ 2,432,328		$ (224,328)		$ 2,058,980
Beginning balance, shares at Jun. 30, 2018		184,316,000				(41,636,000)
Common stock issued on exercise of options (note 11)		$ 1		12,329								12,330
Common stock issued on exercise of options (note 11), shares		252,000
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11)		$ 3		(28,104)								(28,101)
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11), shares		638,000
Common stock issued on employee stock purchase plan (note 11)		$ 1		24,364								$ 24,365
Common stock issued on employee stock purchase plan (note 11), shares		285,000										285,000
Treasury stock purchases		$ (1)				$ (22,844)						$ (22,845)
Treasury stock purchases, shares						(200,000)
Stock-based compensation costs				52,063								52,063
Other comprehensive income (loss)										(28,681)		(28,681)
Net income (loss)								404,592				404,592
Dividends declared								(211,712)				(211,712)
Ending balance at Jun. 30, 2019		$ 575		1,511,473		$ (1,623,256)	$ (188,798)	2,436,410		(253,009)	$ (188,798)	2,072,193
Ending balance, shares at Jun. 30, 2019		185,491,000				(41,836,000)
Common stock issued on exercise of options (note 11)		$ 1		19,986								19,987
Common stock issued on exercise of options (note 11), shares		350,000
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11)		$ 3		(46,061)								(46,058)
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11), shares		617,000
Common stock issued on employee stock purchase plan (note 11)		$ 1		28,196								$ 28,197
Common stock issued on employee stock purchase plan (note 11), shares		265,000										265,000
Stock-based compensation costs				57,100								$ 57,100
Other comprehensive income (loss)										(30,973)		(30,973)
Net income (loss)								621,674				621,674
Dividends declared								(225,093)				(225,093)
Ending balance at Jun. 30, 2020		$ 580		1,570,694		$ (1,623,256)		2,832,991		(283,982)		2,497,027
Ending balance, shares at Jun. 30, 2020		186,723,000				(41,836,000)
Common stock issued on exercise of options (note 11)				3,954								$ 3,954
Common stock issued on exercise of options (note 11), shares		64,000										64,000
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11)		$ 2		(50,209)								$ (50,207)
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11), shares		469,000
Common stock issued on employee stock purchase plan (note 11)		$ 1		33,833								$ 33,834
Common stock issued on employee stock purchase plan (note 11), shares		229,000										229,000
Stock-based compensation costs				63,927								$ 63,927
Other comprehensive income (loss)										90,495		90,495
Net income (loss)								474,505				474,505
Dividends declared								(226,713)				(226,713)
Ending balance at Jun. 30, 2021		$ 583		$ 1,622,199		$ (1,623,256)	$ (1,143)	$ 3,079,640		$ (193,487)	$ (1,143)	$ 2,885,679
Ending balance, shares at Jun. 30, 2021		187,485,000				(41,836,000)