CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]
Common shareholders' equity, beginning balance at Sep. 30, 2010	$ 2,178,348	$ 451	$ 1,714,364	$ (23,372)	$ 486,905
Common stock shares outstanding, balance at Sep. 30, 2010		90,164,103
Net income	207,601				207,601
Other comprehensive income (loss)	(25,088)			(25,088)
Repurchase of common stock, shares		(375,468)
Repurchase of common stock, amount	0	(2)	2
Repurchase of equity awards, shares		(169,793)
Repurchase of equity awards, amount	(5,299)	(1)	(5,298)
Cash dividends	(124,011)				(124,011)
Common stock issued:
Direct stock purchase plan, shares		0
Direct stock purchase plan, amount	(54)	0	(54)
1998 Long-term incentive plan, shares		675,255
1998 Long-term incentive plan, amount	13,889	3	13,886		0
Employee stock-based compensation	9,958		9,958
Outside directors stock-for-fee plan, shares		2,385
Outside directors stock-for-fee-plan, amount	77		77
Common shareholders' equity, ending balance at Sep. 30, 2011	2,255,421	451	1,732,935	(48,460)	570,495
Common stock shares outstanding, ending balance at Sep. 30, 2011		90,296,482
Net income	216,717				216,717
Other comprehensive income (loss)	853			853
Repurchase of common stock, shares		(387,991)
Repurchase of common stock, amount	(12,535)	(2)	(12,533)
Repurchase of equity awards, shares		(153,255)
Repurchase of equity awards, amount	(5,219)	0	(5,219)
Cash dividends	(125,796)				(125,796)
Common stock issued:
Direct stock purchase plan, amount	(65)	0	(65)
1998 Long-term incentive plan, shares		482,289
1998 Long-term incentive plan, amount	12,037	2	12,519		(484)
Employee stock-based compensation	17,752		17,752
Outside directors stock-for-fee plan, shares		2,375
Outside directors stock-for-fee-plan, amount	78		78
Common shareholders' equity, ending balance at Sep. 30, 2012	2,359,243	451	1,745,467	(47,607)	660,932
Common stock shares outstanding, ending balance at Sep. 30, 2012		90,239,900
Net income	243,194				243,194
Other comprehensive income (loss)	86,485			86,485
Repurchase of equity awards, shares		(133,449)
Repurchase of equity awards, amount	(5,150)	0	(5,150)
Cash dividends	(128,115)				(128,115)
Common stock issued:
Direct stock purchase plan, amount	(50)	0	(50)
1998 Long-term incentive plan, shares		531,672
1998 Long-term incentive plan, amount	8,788	2	9,530		(744)
Employee stock-based compensation	15,934		15,934
Outside directors stock-for-fee plan, shares		2,088
Outside directors stock-for-fee-plan, amount	80		80
Common shareholders' equity, ending balance at Sep. 30, 2013	$ 2,580,409	$ 453	$ 1,765,811	$ 38,878	$ 775,267
Common stock shares outstanding, ending balance at Sep. 30, 2013		90,640,211