Earnings Per Common Share (Details) (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Earnings Per Common Share
Net Income, Basic	$ 75,285	$ 58,994	$ 198,747	$ 192,733
Shares, Basic	64,820,000	64,427,000	64,689,000	64,375,000
Per Share Amount, Basic	$ 1.16	$ 0.92	$ 3.07	$ 2.99
Effect of dilutive securities: Stock options, Shares	650,000	610,000	666,000	679,000
Effect of dilutive securities: Stock options, Per Share Amount	$ (0.01)	$ (0.01)	$ (0.03)	$ (0.03)
Net Income, Diluted	$ 75,285	$ 58,994	$ 198,747	$ 192,733
Shares, Diluted	65,470,000	65,037,000	65,355,000	65,054,000
Per Share Amount, Diluted	$ 1.15	$ 0.91	$ 3.04	$ 2.96
Outstanding stock options excluded in the calculation of earnings per share	684,000	508,000	684,000	508,000