Regulatory Assets and Liabilities and Regulatory Matters (Tables)

3 Months Ended

Dec. 31, 2012

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:

	December 31, 2012		September 30, 2012		December 31, 2011
Regulatory assets:
Income taxes recoverable	$	103,665	$	103,172	$	98,741
Underfunded pension and postretirement plans	184,764		188,222		148,650
Environmental costs	17,119		16,812		19,372
Deferred fuel and power costs	7,797		11,602		14,798
Removal costs, net	11,541		12,718		11,946
Other	5,742		5,879		7,984
Total regulatory assets	$	330,628	$	338,405	$	301,491
Regulatory liabilities:
Postretirement benefits	$	13,486	$	13,147	$	11,764
Environmental overcollections	3,077		2,883		4,740
Deferred fuel and power refunds	1,916		4,435		5,019
State tax benefits — distribution system repairs	7,750		7,385		6,509
Other	570		494		377
Total regulatory liabilities	$	26,799	$	28,344	$	28,409