Consolidated Statements Of Stockholders' 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, 2017		$ 569		$ 1,379,130		$ (1,546,611)		$ 2,316,237		$ (189,059)		$ 1,960,266
Beginning balance, shares at Jun. 30, 2017		183,261,000				(41,086,000)
Common stock issued on exercise of options (note 11)		$ 2		18,759								18,761
Common stock issued on exercise of options (note 11), shares		539,000
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11)		$ 1		(15,385)								(15,384)
Common stock issued on vesting of restricted stock units, net of shares withheld for tax (note 11), shares		214,000
Common stock issued on employee stock purchase plan (note 11)		$ 1		19,955								$ 19,956
Common stock issued on employee stock purchase plan (note 11), shares		302,000										302,000
Treasury stock purchases		$ (2)				$ (53,801)						$ (53,803)
Treasury stock purchases, shares						(550,000)
Stock-based compensation costs				48,362								48,362
Other comprehensive income										(35,269)		(35,269)
Net income								315,588				315,588
Dividends declared								(199,497)				(199,497)
Ending balance at Jun. 30, 2018		$ 571		1,450,821		$ (1,600,412)		2,432,328		(224,328)		2,058,980
Ending 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										(28,681)		(28,681)
Net income								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										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
Treasury stock purchases
Treasury stock purchases, shares
Stock-based compensation costs				57,100								57,100
Other comprehensive income										(30,973)		(30,973)
Net income								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)