Condensed Consolidated Balance Sheets (unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012
Current assets:
Cash and cash equivalents	$ 82,027	$ 1,259	$ 75,969
Restricted cash	2,636	0	1,604
Accounts receivable (less allowances for doubtful accounts of $9,166, $3,588 and $7,457, respectively)	78,677	47,362	61,072
Accounts receivable — related parties	4,086	4,571	4,311
Accrued utility revenues	11,836	16,911	14,970
Inventories	53,998	67,334	38,413
Deferred income taxes	38,619	46,436	33,595
Regulatory assets	3,747	6,473	2,681
Derivative financial instruments	8,228	5,468	545
Prepaid expenses & other current assets	9,766	29,313	17,890
Total current assets	293,620	225,127	251,050
Property, plant and equipment, at cost (less accumulated depreciation and amortization of $846,941, $815,720 and $809,458, respectively)	1,531,440	1,479,949	1,458,654
Goodwill	182,145	182,145	182,145
Regulatory assets	317,216	331,932	288,366
Other assets	3,635	4,026	5,630
Total assets	2,328,056	2,223,179	2,185,845
Current liabilities:
Current maturities of long-term debt	133,000	133,000	40,000
Bank loans	0	9,200	0
Accounts payable	35,587	46,754	30,457
Accounts payable — related parties	17,176	10,192	10,175
Deferred fuel refunds	14,156	4,435	10,325
Derivative financial instruments	22,911	36,011	7,150
Other current liabilities	123,438	131,092	144,492
Total current liabilities	346,268	370,684	242,599
Long-term debt	467,000	467,000	600,000
Deferred income taxes	443,703	417,052	371,388
Deferred investment tax credits	4,355	4,612	4,698
Pension and postretirement benefit obligations	172,721	179,056	126,007
Other noncurrent liabilities	51,999	56,262	92,409
Total liabilities	1,486,046	1,494,666	1,437,101
Commitments and contingencies (note 8)
Common stockholder’s equity:
Common Stock, $2.25 par value (authorized — 40,000,000 shares; issued and outstanding — 26,781,785 shares)	60,259	60,259	60,259
Additional paid-in capital	469,736	468,692	468,630
Retained earnings	327,298	229,379	246,286
Accumulated other comprehensive loss	(15,283)	(29,817)	(26,431)
Total common stockholder’s equity	842,010	728,513	748,744
Total liabilities and stockholder’s equity	$ 2,328,056	$ 2,223,179	$ 2,185,845