Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statements Of Comprehensive Income [Abstract]
Net Income Available for Common Stock	$ 67,944	$ 60,699
Other Comprehensive Income (Loss), Before Tax:
Unrealized Gain on Securities Available for Sale Arising During the Period	789	712
Unrealized Gain on Derivative Financial Instruments Arising During the Period	35,350	2,155
Reclassification Adjustment for Realized Gains on Derivative Financial Instruments in Net Income	(11,584)	(11,864)
Other Comprehensive Income (Loss), Before Tax	24,555	(8,997)
Income Tax Expense Related to Unrealized Gain On Securities Available for Sale Arising During the Period	295	263
Income Tax Expense Related to Unrealized Gain on Derivative Financial Instruments Arising During the Period	14,738	817
Reclassification Adjustment for Income Tax Expense on Realized Gains from Derivative Financial Instruments In Net Income	(4,854)	(4,644)
Income Taxes - Net	10,179	(3,564)
Other Comprehensive Income (Loss)	14,376	(5,433)
Comprehensive Income	$ 82,320	$ 55,266