Segment Information (Tables)

9 Months Ended

Jun. 30, 2016

Segment Reporting [Abstract]

Schedule of Segment Information

Financial information by business segment follows:

Three Months Ended June 30, 2016:

			Reportable Segments
	Total		Gas Utility		Electric Utility
Revenues	$	140,283	$	119,995	$	20,288
Cost of sales	$	44,415	$	33,715	$	10,700
Depreciation and amortization	$	16,550	$	15,339	$	1,211
Operating income	$	29,815	$	27,116	$	2,699
Interest expense	$	9,158	$	8,670	$	488
Income before income taxes	$	20,657	$	18,446	$	2,211
Capital expenditures (including the effects of accruals)	$	56,481	$	53,199	$	3,282

Three Months Ended June 30, 2015:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	143,490	$	119,412	$	23,875	$	203
Cost of sales	$	53,691	$	41,352	$	12,339	$	—
Depreciation and amortization	$	15,913	$	14,786	$	1,127	$	—
Operating income	$	20,184	$	15,099	$	4,071	$	1,014
Interest expense	$	9,985	$	9,483	$	502	$	—
Income before income taxes	$	10,199	$	5,616	$	3,569	$	1,014
Capital expenditures (including the effects of accruals)	$	43,315	$	41,324	$	1,991	$	—

Nine Months Ended June 30, 2016:

			Reportable Segments
	Total		Gas Utility		Electric Utility
Revenues	$	660,312	$	595,025	$	65,287
Cost of sales	$	257,288	$	221,646	$	35,642
Depreciation and amortization	$	50,281	$	46,665	$	3,616
Operating income	$	192,592	$	183,940	$	8,652
Interest expense	$	27,922	$	26,583	$	1,339
Income before income taxes	$	164,670	$	157,357	$	7,313
Capital expenditures (including the effects of accruals)	$	166,058	$	158,472	$	7,586
As of June 30, 2016
Total assets (at period end)	$	2,699,898	$	2,534,039	$	165,859
Goodwill (at period end)	$	182,145	$	182,145	$	—

Nine Months Ended June 30, 2015:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	931,369	$	847,890	$	82,621	$	858
Cost of sales	$	475,079	$	426,715	$	48,364	$	—
Depreciation and amortization	$	46,982	$	43,555	$	3,427	$	—
Operating income	$	238,523	$	226,248	$	11,300	$	975
Interest expense	$	31,245	$	29,717	$	1,528	$	—
Income before income taxes	$	207,278	$	196,531	$	9,772	$	975
Capital expenditures (including the effects of accruals)	$	139,624	$	134,018	$	5,606	$	—
As of June 30, 2015
Total assets (at period end)	$	2,423,205	$	2,278,975	$	144,230	$	—
Goodwill (at period end)	$	182,145	$	182,145	$	—	$	—