Earnings Per Share (Details) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Basic Earnings per Share from Continuing Operations
Income (loss) from continuing operations	$ 105,910,000	$ 128,160,000	$ 171,698,000	$ 199,260,000
Less: Income (loss) from continuing operations allocated to participating securities	1,109,000	1,342,000	1,794,000	2,089,000
Income (loss) from continuing operations available to common shareholders	104,801,000	126,818,000	169,904,000	197,171,000
Income Loss From Continuing Operations Per Basic Share	$ 1.16	$ 1.41	$ 1.89	$ 2.18
Basic Earnings per Share from Discontinued Operations
Income (loss) from discontinued operations	3,201,000	4,049,000	5,920,000	6,946,000
Less: Income (loss) from discontinued operations allocated to participating securities	34,000	42,000	62,000	73,000
Income (loss) from discontinued operations available to common shareholders	3,167,000	4,007,000	5,858,000	6,873,000
Income (loss) from discontinued operations per share - Basic	$ 0.04	$ 0.04	$ 0.06	$ 0.08
Basic net income (loss) per share	$ 1.20	$ 1.45	$ 1.95	$ 2.26
Basic	90,020,000	90,246,000	90,137,000	90,157,000
Diluted Earnings per Share from Continuing Operations
Effect of dilutive stock options and other shares	3,000	3,000	4,000	5,000
Income (loss) from continuing operations available to common shareholders	104,804,000	126,821,000	169,908,000	197,176,000
Additional dilutive stock options and other shares	302,000	287,000	303,000	298,000
Diluted	90,322,000	90,533,000	90,440,000	90,455,000
Income Loss From Continuing Operations Per Diluted Share	$ 1.16	$ 1.41	$ 1.88	$ 2.18
Diluted Earnings per Share from Discontinued Operations
Effect of dilutive stock options and other shares	0	0	0	0
Income (loss) from discontinued operations available to common shareholders	3,167,000	4,007,000	5,858,000	6,873,000
Additional dilutive stock options and other shares	302,000	287,000	303,000	298,000
Diluted weighted average shares outstanding	90,322,000	90,533,000	90,440,000	90,455,000
Income (loss) from discontinued operations per share - Diluted	$ 0.04	$ 0.04	$ 0.06	$ 0.08
Diluted net income (loss) per share	$ 1.20	$ 1.45	$ 1.94	$ 2.26
Earnings Per Share Diluted Other Disclosures Abstract
Share Repurchase Program - Shares Purchased			387,991
Share Repurchase Program - Number of Shares Authorized	5,000,000		5,000,000
Share Repurchase Program - Years Authorized	5		5
Share Repurchase Program - Amount Purchased			$ 12,500,000