Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016
Current assets:
Cash and cash equivalents	$ 4,566	$ 2,819	$ 26,406
Restricted cash	347	583	3,909
Accounts receivable (less allowances for doubtful accounts of $9,401, $3,946 and $8,232, respectively)	123,285	44,692	102,125
Accounts receivable — related parties	1,739	398	1,271
Accrued utility revenues	36,665	12,753	24,052
Inventories	17,174	42,340	16,685
Prepaid income taxes	301	1,956	0
Regulatory assets	2,309	3,208	3,229
Derivative instruments	2,024	4,263	881
Prepaid expenses & other current assets	22,957	22,009	27,632
Total current assets	211,367	135,021	206,190
Property, plant and equipment, at cost (less accumulated depreciation and amortization of $997,591, $975,374 and $952,478, respectively)	2,112,013	2,023,541	1,900,806
Goodwill	182,145	182,145	182,145
Regulatory assets	392,408	391,933	344,983
Other assets	11,792	10,451	5,395
Total assets	2,909,725	2,743,091	2,639,519
Current liabilities:
Current maturities of long-term debt	59,980	19,986	0
Short-term borrowings	48,500	112,500	155,000
Accounts payable	58,095	65,180	42,681
Accounts payable — related parties	11,339	3,995	6,710
Regulatory liability — deferred fuel and power refunds	13,791	22,299	30,838
Derivative instruments	19	310	3,370
Other current liabilities	126,342	109,640	152,479
Total current liabilities	318,066	333,910	391,078
Long-term debt	711,066	651,455	547,932
Deferred income taxes	590,964	550,229	526,937
Deferred investment tax credits	3,109	3,268	3,429
Pension and postretirement benefit obligations	179,101	184,516	130,915
Other noncurrent liabilities	96,838	94,976	99,029
Total liabilities	1,899,144	1,818,354	1,699,320
Commitments and contingencies (Note 7)
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	473,580	473,580	472,715
Retained earnings	506,906	422,516	436,788
Accumulated other comprehensive loss	(30,164)	(31,618)	(29,563)
Total common stockholder’s equity	1,010,581	924,737	940,199
Total liabilities and stockholder’s equity	$ 2,909,725	$ 2,743,091	$ 2,639,519