Regulatory Assets and Liabilities and Regulatory Matters (Tables)

3 Months Ended

Dec. 31, 2015

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of 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, 2015		September 30, 2015		December 31, 2014
Regulatory assets:
Income taxes recoverable	$	117,396	$	115,946	$	111,075
Underfunded pension and postretirement plans	138,294		140,762		107,827
Environmental costs	17,643		19,983		14,738
Deferred fuel and power costs	—		—		16,761
Removal costs, net	22,346		21,223		17,550
Other	6,140		6,294		2,648
Total regulatory assets	$	301,819	$	304,208	$	270,599
Regulatory liabilities:
Postretirement benefits	$	20,314	$	19,975	$	18,959
Deferred fuel and power refunds	28,083		36,638		—
State tax benefits — distribution system repairs	13,712		13,266		10,349
Other	1,073		1,125		3,580
Total regulatory liabilities (a)	$	63,182	$	71,004	$	32,888

(a) Regulatory liabilities, other than deferred fuel and power refunds, are recorded in other current and noncurrent liabilities in the Condensed Consolidated Balance Sheets.