Business Segments (Details) (USD $)	3 Months Ended		6 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Segment Reporting Information [Line Items]
Revenues from External Customers	$ 462,247,000	$ 399,411,000	$ 1,119,980,000	$ 915,286,000
Margin	211,523,000	183,856,000	473,035,000	415,480,000
Operations And Maintenance Expenses	70,214,000	65,103,000	130,878,000	121,039,000
Income From Equity Method Investments	14,360,000	12,437,000	24,302,000	19,592,000
Operating Income (Loss) Before Income Taxes	103,464,000	82,814,000	265,477,000	222,191,000
Income (Loss) Before Income Taxes	103,334,000	92,045,000	264,436,000	233,941,000
Number Of Operating Segments	2
Regulated Operation [Member]
Segment Reporting Information [Line Items]
Revenues from External Customers	462,247,000	399,411,000	1,119,980,000	915,286,000
Margin	211,523,000	183,856,000	473,035,000	415,480,000
Operations And Maintenance Expenses	70,193,000	65,037,000	130,832,000	120,919,000
Income From Equity Method Investments	0	0	0	0
Operating Income (Loss) Before Income Taxes	103,489,000	82,884,000	265,610,000	222,396,000
Income (Loss) Before Income Taxes	88,999,000	79,678,000	240,268,000	214,555,000
Non Utility Activities [Member]
Segment Reporting Information [Line Items]
Revenues from External Customers	0	0	0	0
Margin	0	0	0	0
Operations And Maintenance Expenses	21,000	66,000	46,000	120,000
Income From Equity Method Investments	14,360,000	12,437,000	24,302,000	19,592,000
Operating Income (Loss) Before Income Taxes	(25,000)	(70,000)	(133,000)	(205,000)
Income (Loss) Before Income Taxes	$ 14,335,000	$ 12,367,000	$ 24,168,000	$ 19,386,000