Consolidated Statement Of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Jun. 30, 2017	$ 1,712,832	$ 1,080	$ 1,137,724	$ 868,822	$ (99,315)	$ (195,479)
Balance, shares at Jun. 30, 2017		107,989			4,287
Increase (Decrease) in Stockholders' Equity
Net income	19,846			19,846
Other comprehensive loss	33,787					33,787
Issuance of common stock pursuant to stock-based compensation plans	0	$ 1	(1)
Issuance of common stock pursuant to stock-based compensation plans, shares		98
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(2,098)				$ (2,098)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans, shares					52
Stock-based compensation expense	3,164		3,164
Balance at Sep. 30, 2017	1,767,531	$ 1,081	1,140,887	888,668	$ (101,413)	(161,692)
Balance, shares at Sep. 30, 2017		108,087			4,339
Balance at Jun. 30, 2017	1,712,832	$ 1,080	1,137,724	868,822	$ (99,315)	(195,479)
Balance, shares at Jun. 30, 2017		107,989			4,287
Increase (Decrease) in Stockholders' Equity
Net income	79,635
Other comprehensive loss	79,895
Balance at Mar. 31, 2018	1,875,767	$ 1,084	1,147,978	948,457	$ (106,168)	(115,584)
Balance, shares at Mar. 31, 2018		108,383			4,458
Balance at Sep. 30, 2017	1,767,531	$ 1,081	1,140,887	888,668	$ (101,413)	(161,692)
Balance, shares at Sep. 30, 2017		108,087			4,339
Increase (Decrease) in Stockholders' Equity
Net income	47,103			47,103
Other comprehensive loss	8,341					8,341
Issuance of common stock pursuant to stock-based compensation plans	0	$ 3	(3)
Issuance of common stock pursuant to stock-based compensation plans, shares		284
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(4,587)				$ (4,587)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans, shares					114
Stock-based compensation expense	4,158		4,158
Balance at Dec. 31, 2017	1,822,546	$ 1,084	1,145,042	935,771	$ (106,000)	(153,351)
Balance, shares at Dec. 31, 2017		108,371			4,453
Increase (Decrease) in Stockholders' Equity
Net income	12,686			12,686
Other comprehensive loss	37,767					37,767
Issuance of common stock pursuant to stock-based compensation plans	0	$ 0	0
Issuance of common stock pursuant to stock-based compensation plans, shares		12
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(168)				$ (168)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans, shares					5
Stock-based compensation expense	2,936		2,936
Balance at Mar. 31, 2018	1,875,767	$ 1,084	1,147,978	948,457	$ (106,168)	(115,584)
Balance, shares at Mar. 31, 2018		108,383			4,458
Balance at Jun. 30, 2018	$ 1,737,049	$ 1,084	1,148,196	878,516	$ (106,507)	(184,240)
Balance, shares at Jun. 30, 2018	108,422	108,422			4,470
Increase (Decrease) in Stockholders' Equity
Net income	$ (37,425)			(37,425)
Other comprehensive loss	(13,519)					(13,519)
Issuance of common stock pursuant to stock-based compensation plans	0	$ 1	(1)
Issuance of common stock pursuant to stock-based compensation plans, shares		85
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(979)				$ (979)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans, shares					35
Stock-based compensation expense	135		135
Balance at Sep. 30, 2018	1,685,424	$ 1,085	1,148,330	840,906	$ (107,486)	(197,411)
Balance, shares at Sep. 30, 2018		108,507			4,505
Balance at Jun. 30, 2018	$ 1,737,049	$ 1,084	1,148,196	878,516	$ (106,507)	(184,240)
Balance, shares at Jun. 30, 2018	108,422	108,422			4,470
Increase (Decrease) in Stockholders' Equity
Net income	$ (169,763)
Other comprehensive loss	(20,575)
Balance at Mar. 31, 2019	$ 1,549,792	$ 1,087	1,154,182	708,568	$ (109,578)	(204,467)
Balance, shares at Mar. 31, 2019	108,713	108,713			4,592
Balance at Sep. 30, 2018	$ 1,685,424	$ 1,085	1,148,330	840,906	$ (107,486)	(197,411)
Balance, shares at Sep. 30, 2018		108,507			4,505
Increase (Decrease) in Stockholders' Equity
Net income	(66,501)			(66,501)
Other comprehensive loss	(27,948)					(27,948)
Issuance of common stock pursuant to stock-based compensation plans	0	$ 2	(2)
Issuance of common stock pursuant to stock-based compensation plans, shares		184
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(1,943)				$ (1,943)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans, shares					79
Stock-based compensation expense	1,911		1,911
Balance at Dec. 31, 2018	1,590,943	$ 1,087	1,150,239	774,405	$ (109,429)	(225,359)
Balance, shares at Dec. 31, 2018		108,691			4,584
Increase (Decrease) in Stockholders' Equity
Net income	(65,837)			(65,837)
Other comprehensive loss	20,892					20,892
Issuance of common stock pursuant to stock-based compensation plans	0	$ 0	0
Issuance of common stock pursuant to stock-based compensation plans, shares		22
Shares withheld for payment of employee payroll taxes due on shares issued under stock-based compensation plans	(149)				$ (149)
Shares withheld for payment of employee payroll taxes due on shares issued under stock based compensation plans, shares					8
Stock-based compensation expense	3,943		3,943
Balance at Mar. 31, 2019	$ 1,549,792	$ 1,087	$ 1,154,182	$ 708,568	$ (109,578)	$ (204,467)
Balance, shares at Mar. 31, 2019	108,713	108,713			4,592