CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Retained earnings	$ 686,063
Balance at Jun. 30, 2017	268,759	$ 10,257	$ 687,479	$ 686,063	$ 1,459	$ (1,116,499)
Balance (in shares) at Jun. 30, 2017		102,567,129				29,145,976
Comprehensive income (loss):
Net income	281,234			281,234
Other comprehensive loss	(71)				(71)
Exercise of stock options	13,431	$ 36	13,395
Exercise of stock options (in shares)		362,515
Issuance of restricted stock units and net share settlement related to withholding taxes	(8,067)	$ 20	(8,087)
Issuance of restricted stock units and net share settlement related to withholding taxes (in shares)		200,656
Repurchase of common stock	$ (200,000)					$ (200,000)
Repurchase of common stock (in shares)	2,797,623					2,797,623
Stock-based compensation	$ 22,688		22,688
Balance at Jun. 30, 2018	377,974	$ 10,313	715,475	967,297	1,388	$ (1,316,499)
Balance (in shares) at Jun. 30, 2018		103,130,300				31,943,599
Retained earnings	967,297
Comprehensive income (loss):
Net income	261,362			261,362
Other comprehensive loss	(1,052)				(1,052)
Exercise of stock options	10,830	$ 27	10,803
Exercise of stock options (in shares)		266,014
Issuance of restricted stock units and net share settlement related to withholding taxes	(14,727)	$ 25	(14,752)
Issuance of restricted stock units and net share settlement related to withholding taxes (in shares)		245,978
Repurchase of common stock	$ (300,000)					$ (300,000)
Repurchase of common stock (in shares)	3,074,127					3,074,127
Stock-based compensation	$ 27,573		27,573
Balance at Jun. 30, 2019	$ 361,960	$ 10,365	739,099	1,228,659	336	$ (1,616,499)
Balance (in shares) at Jun. 30, 2019	103,642,292	103,642,292				35,017,726
Retained earnings	$ 1,228,659
Comprehensive income (loss):
Net income	229,671			229,671
Other comprehensive loss	(5,624)				(5,624)
Exercise of stock options	8,938	$ 17	8,921
Exercise of stock options (in shares)		173,390
Issuance of restricted stock units and net share settlement related to withholding taxes	(10,140)	$ 17	(10,157)
Issuance of restricted stock units and net share settlement related to withholding taxes (in shares)		173,025
Repurchase of common stock	$ (150,000)					$ (150,000)
Repurchase of common stock (in shares)	1,252,289					1,252,289
Stock-based compensation	$ 31,548		31,548
Balance at Jun. 30, 2020	$ 466,353	$ 10,399	$ 769,411	$ 1,458,330	$ (5,288)	$ (1,766,499)
Balance (in shares) at Jun. 30, 2020	103,988,707	103,988,707				36,270,015
Retained earnings	$ 1,458,330