Regulatory Assets and Liabilities and Regulatory Matters (Tables)

6 Months Ended

Mar. 31, 2013

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory assets and liabilities associated with Gas Utility and Electric Utility

The following regulatory assets and liabilities associated with Gas Utility and Electric Utility are included in our accompanying Condensed Consolidated Balance Sheets:

	March 31, 2013		September 30, 2012		March 31, 2012
Regulatory assets:
Income taxes recoverable	$	104,229	$	103,172	$	99,226
Underfunded pension and postretirement plans	181,305		188,222		146,631
Environmental costs	16,841		16,812		18,247
Deferred fuel and power costs	2,122		11,602		11,012
Removal costs, net	11,856		12,718		11,915
Other	5,976		5,879		8,658
Total regulatory assets	$	322,329	$	338,405	$	295,689
Regulatory liabilities:
Postretirement benefits	$	13,865	$	13,147	$	12,053
Environmental overcollections	2,980		2,883		3,843
Deferred fuel and power refunds	31,209		4,435		12,022
State tax benefits — distribution system repairs	7,900		7,385		6,735
Other	700		494		747
Total regulatory liabilities	$	56,654	$	28,344	$	35,400