CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Jun. 30, 2019	$ 1,519,319	$ (439)	$ 1,088	$ 1,158,257	$ 695,017	$ (439)	$ (110,039)	$ (225,004)
Beginning balance (shares) at Jun. 30, 2019			108,833				4,614
Increase (Decrease) in Stockholders' Equity
Net income	(107,021)				(107,021)
Other comprehensive income (loss)	56,110							56,110
Issuance of common stock pursuant to stock-based compensation plans	0		$ 1	(1)
Issuance of common stock pursuant to stock-based compensation plans (shares)			40
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(312)						$ (312)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans (shares)							17
Stock-based compensation expense	3,281			3,281
Ending balance at Sep. 30, 2019	1,470,938		$ 1,089	1,161,537	587,557		$ (110,351)	(168,894)
Ending balance (shares) at Sep. 30, 2019			108,873				4,631
Beginning balance at Jun. 30, 2019	1,519,319	(439)	$ 1,088	1,158,257	695,017	(439)	$ (110,039)	(225,004)
Beginning balance (shares) at Jun. 30, 2019			108,833				4,614
Increase (Decrease) in Stockholders' Equity
Net income	(83,646)
Ending balance at Mar. 31, 2020	1,439,048		$ 1,092	1,168,378	610,932		$ (168,951)	(172,403)
Ending balance (shares) at Mar. 31, 2020			109,089				7,117
Beginning balance at Jun. 30, 2019	1,519,319	(439)	$ 1,088	1,158,257	695,017	(439)	$ (110,039)	(225,004)
Beginning balance (shares) at Jun. 30, 2019			108,833				4,614
Ending balance at Jun. 30, 2020	$ 1,443,554	(310)	$ 1,092	1,171,875	614,171	(310)	$ (172,192)	(171,392)
Ending balance (shares) at Jun. 30, 2020	109,123		109,123				7,238
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance at Sep. 30, 2019	$ 1,470,938		$ 1,089	1,161,537	587,557		$ (110,351)	(168,894)
Beginning balance (shares) at Sep. 30, 2019			108,873				4,631
Increase (Decrease) in Stockholders' Equity
Net income	(964)				(964)
Other comprehensive income (loss)	48,697							48,697
Issuance of common stock pursuant to stock-based compensation plans	0		$ 2	(2)
Issuance of common stock pursuant to stock-based compensation plans (shares)			146
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(671)						$ (671)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans (shares)							27
Stock-based compensation expense	3,083			3,083
Ending balance at Dec. 31, 2019	1,521,083		$ 1,091	1,164,618	586,593		$ (111,022)	(120,197)
Ending balance (shares) at Dec. 31, 2019			109,019				4,658
Increase (Decrease) in Stockholders' Equity
Net income	24,339				24,339
Other comprehensive income (loss)	(52,206)							(52,206)
Issuance of common stock pursuant to stock-based compensation plans	0		$ 1	(1)
Issuance of common stock pursuant to stock-based compensation plans (shares)			70
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(523)						$ (523)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans (shares)							20
Repurchases of common stock	(57,406)						$ (57,406)
Repurchases of common stock (shares)							2,439
Stock-based compensation expense	3,761			3,761
Ending balance at Mar. 31, 2020	1,439,048		$ 1,092	1,168,378	610,932		$ (168,951)	(172,403)
Ending balance (shares) at Mar. 31, 2020			109,089				7,117
Beginning balance at Jun. 30, 2020	$ 1,443,554	(310)	$ 1,092	1,171,875	614,171	(310)	$ (172,192)	(171,392)
Beginning balance (shares) at Jun. 30, 2020	109,123		109,123				7,238
Increase (Decrease) in Stockholders' Equity
Net income	$ 485				485
Other comprehensive income (loss)	31,005							31,005
Issuance of common stock pursuant to stock-based compensation plans	0		$ 1	(1)
Issuance of common stock pursuant to stock-based compensation plans (shares)			54
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(468)						$ (468)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans (shares)							20
Repurchases of common stock	(42,052)						$ (42,052)
Repurchases of common stock (shares)							1,281
Stock-based compensation expense	4,367			4,367
Ending balance at Sep. 30, 2020	1,436,581		$ 1,093	1,176,241	614,346		$ (214,712)	(140,387)
Ending balance (shares) at Sep. 30, 2020			109,177				8,539
Beginning balance at Jun. 30, 2020	$ 1,443,554	$ (310)	$ 1,092	1,171,875	614,171	$ (310)	$ (172,192)	(171,392)
Beginning balance (shares) at Jun. 30, 2020	109,123		109,123				7,238
Increase (Decrease) in Stockholders' Equity
Net income	$ 36,879
Ending balance at Mar. 31, 2021	$ 1,501,682		$ 1,096	1,183,759	650,740		$ (256,231)	(77,682)
Ending balance (shares) at Mar. 31, 2021	109,466		109,466				9,753
Beginning balance at Sep. 30, 2020	$ 1,436,581		$ 1,093	1,176,241	614,346		$ (214,712)	(140,387)
Beginning balance (shares) at Sep. 30, 2020			109,177				8,539
Increase (Decrease) in Stockholders' Equity
Net income	2,140				2,140
Other comprehensive income (loss)	43,044							43,044
Issuance of common stock pursuant to stock-based compensation plans	0		$ 2	(2)
Issuance of common stock pursuant to stock-based compensation plans (shares)			162
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(1,255)						$ (1,255)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans (shares)							38
Repurchases of common stock	(29,684)						$ (29,684)
Repurchases of common stock (shares)							923
Stock-based compensation expense	3,823			3,823
Ending balance at Dec. 31, 2020	1,454,649		$ 1,095	1,180,062	616,486		$ (245,651)	(97,343)
Ending balance (shares) at Dec. 31, 2020			109,339				9,500
Increase (Decrease) in Stockholders' Equity
Net income	34,254				34,254
Other comprehensive income (loss)	19,661							19,661
Issuance of common stock pursuant to stock-based compensation plans	0		$ 1	(1)
Issuance of common stock pursuant to stock-based compensation plans (shares)			127
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(2,018)						$ (2,018)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans (shares)							49
Repurchases of common stock	(8,562)						$ (8,562)
Repurchases of common stock (shares)							204
Stock-based compensation expense	3,698			3,698
Ending balance at Mar. 31, 2021	$ 1,501,682		$ 1,096	$ 1,183,759	$ 650,740		$ (256,231)	$ (77,682)
Ending balance (shares) at Mar. 31, 2021	109,466		109,466				9,753