Income Taxes Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax at statutory rate of 35%	$ 178,768	$ 166,887	$ 130,655
Common stock dividends deductible for tax reporting	(2,413)	(2,307)	(2,153)
State taxes (net of federal benefit)	12,869	11,636	11,559
Change in valuation allowance	4,998	6,969	1,085
Other, net	1,468	3,817	1,453
Income tax expense (benefit)	$ 195,690	$ 187,002	$ 142,599