CONSOLIDATED CONDENSED STATEMENT OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Total
Balance at beginning of period at Sep. 30, 2017	$ 11,196	$ 487,248	$ 3,855,686	$ 2,300	$ (191,839)	$ 4,164,591
Balance (in shares) at Sep. 30, 2017	111,957,000					111,956,875
Balance (in shares) at Sep. 30, 2017					3,353,000
Increase (Decrease) in Shareholders' Equity
Net income (loss)			488,227			$ 488,227
Other comprehensive income (loss)				(7,521)		(7,521)
Dividends declared			(153,861)			(153,861)
Exercise of stock options, net of shares withheld for employee taxes		(5,063)			$ 5,005	(58)
Exercise of stock options, net of tax withholding (in shares)	1,000				(90,000)
Stock issued for vested restricted stock, net of shares withheld for employee taxes	$ 5	(11,468)			$ 7,375	(4,088)
Stock issued for vested restricted stock, net of shares withheld for employee taxes (in shares)	51,000				(131,000)
Stock-based compensation		15,546				15,546
Balance at end of period at Mar. 31, 2018	$ 11,201	487,135	4,189,497	(5,221)	$ (179,459)	$ 4,503,153
Balance (in shares) at Mar. 31, 2018	112,009,000					112,008,961
Balance (in shares) at Mar. 31, 2018					3,132,000
Balance at beginning of period at Dec. 31, 2017				2,039
Increase (Decrease) in Shareholders' Equity
Net income (loss)						$ (11,879)
Other comprehensive income (loss)						$ (7,260)
Repurchase of common stock (in shares)						0
Balance at end of period at Mar. 31, 2018	$ 11,201	487,135	4,189,497	$ (5,221)	$ (179,459)	$ 4,503,153
Balance (in shares) at Mar. 31, 2018	112,009,000					112,008,961
Balance (in shares) at Mar. 31, 2018					3,132,000
Increase (Decrease) in Shareholders' Equity
Cumulative effect of adopting Accounting Standards Update 2016-09 | ASU 2016-09		$ 872	$ (555)			$ 317