Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock [Member]	Total
Balance at the beginning of period at Jun. 30, 2021	$ 811	$ 519,826	$ 1,999,405	$ (9,218)	$ (1,217,307)	$ 1,293,517
Balance at the beginning of period (in shares) at Jun. 30, 2021	81,099				31,846
Net income			304,245			304,245
Other comprehensive income (loss), net of tax				12		12
Reclassification adjustment for realized gain on foreign currency translation adjustments				(906)		(906)
Reclassification adjustment for loss on interest rate swap				6,695		6,695
Stock-based compensation		19,240				19,240
Net activity from stock-based compensation awards	$ 7	8,426			$ (2,727)	5,706
Net activity from stock-based compensation awards (in shares)	660				78
Proceeds from stock issued under Colleague Stock Purchase Plan		(61)			$ 505	444
Proceeds from stock issued under Colleague Stock Purchase Plan (in shares)					(13)
Repurchases of common stock for treasury					$ (120,000)	(120,000)
Repurchases of common stock for treasury (in shares)					4,710
Equity forward contract		(30,000)				(30,000)
Balance at the end of period at Mar. 31, 2022	$ 818	517,431	2,303,650	(3,417)	$ (1,339,529)	$ 1,478,953
Balance at the end of period (in shares) at Mar. 31, 2022	81,759				36,621	45,138
Balance at the beginning of period at Dec. 31, 2021	$ 817	542,296	1,955,910	(2,487)	$ (1,219,543)	$ 1,276,993
Balance at the beginning of period (in shares) at Dec. 31, 2021	81,705				31,908
Net income			347,740			347,740
Other comprehensive income (loss), net of tax				(24)		(24)
Reclassification adjustment for realized gain on foreign currency translation adjustments				(906)		(906)
Reclassification adjustment for loss on interest rate swap						0
Stock-based compensation		4,953				4,953
Net activity from stock-based compensation awards	$ 1	232			$ (209)	24
Net activity from stock-based compensation awards (in shares)	54				9
Proceeds from stock issued under Colleague Stock Purchase Plan		(50)			$ 223	173
Proceeds from stock issued under Colleague Stock Purchase Plan (in shares)					(6)
Repurchases of common stock for treasury					$ (120,000)	(120,000)
Repurchases of common stock for treasury (in shares)					4,710
Equity forward contract		(30,000)				(30,000)
Balance at the end of period at Mar. 31, 2022	$ 818	517,431	2,303,650	(3,417)	$ (1,339,529)	$ 1,478,953
Balance at the end of period (in shares) at Mar. 31, 2022	81,759				36,621	45,138
Balance at the beginning of period at Jun. 30, 2022	$ 818	521,848	2,310,396	(2,227)	$ (1,339,449)	$ 1,491,386
Balance at the beginning of period (in shares) at Jun. 30, 2022	81,796				36,619	45,177
Net income			71,114			$ 71,114
Reclassification adjustment for realized gain on foreign currency translation adjustments						0
Reclassification adjustment for loss on interest rate swap						0
Stock-based compensation		10,908				10,908
Net activity from stock-based compensation awards	$ 4	1,617			$ (4,214)	(2,593)
Net activity from stock-based compensation awards (in shares)	375				105
Proceeds from stock issued under Colleague Stock Purchase Plan		(10)	(4)		$ 516	502
Proceeds from stock issued under Colleague Stock Purchase Plan (in shares)					(14)
Settlement of equity forward contract		30,000			$ (43,162)	(13,162)
Repurchases of common stock for treasury					$ (47,770)	(47,770)
Repurchases of common stock for treasury (in shares)					1,229
Balance at the end of period at Mar. 31, 2023	$ 822	564,363	2,381,506	(2,227)	$ (1,434,079)	$ 1,510,385
Balance at the end of period (in shares) at Mar. 31, 2023	82,171				37,939	44,232
Balance at the beginning of period at Dec. 31, 2022	$ 822	561,376	2,335,641	(2,227)	$ (1,386,395)	$ 1,509,217
Balance at the beginning of period (in shares) at Dec. 31, 2022	82,156				36,713
Net income			45,869			45,869
Reclassification adjustment for realized gain on foreign currency translation adjustments						0
Reclassification adjustment for loss on interest rate swap						0
Stock-based compensation		2,795				2,795
Net activity from stock-based compensation awards		199			$ (106)	93
Net activity from stock-based compensation awards (in shares)	15				2
Proceeds from stock issued under Colleague Stock Purchase Plan		(7)	(4)		$ 192	181
Proceeds from stock issued under Colleague Stock Purchase Plan (in shares)					(5)
Repurchases of common stock for treasury					$ (47,770)	(47,770)
Repurchases of common stock for treasury (in shares)					1,229
Balance at the end of period at Mar. 31, 2023	$ 822	$ 564,363	$ 2,381,506	$ (2,227)	$ (1,434,079)	$ 1,510,385
Balance at the end of period (in shares) at Mar. 31, 2023	82,171				37,939	44,232