Segment Information (Tables)

9 Months Ended

Jun. 30, 2015

Segment Reporting [Abstract]

Schedule of Segment Information

Financial information by business segment follows:

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	$	43,315	$	41,324	$	1,991	$	—

Three Months Ended June 30, 2014:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	152,694	$	128,264	$	23,954	$	476
Cost of sales	$	63,323	$	49,257	$	14,066	$	—
Depreciation and amortization	$	14,892	$	13,774	$	1,118	$	—
Operating income	$	19,720	$	17,115	$	2,304	$	301
Interest expense	$	10,433	$	9,904	$	529	$	—
Income before income taxes	$	9,287	$	7,211	$	1,775	$	301
Capital expenditures	$	38,215	$	35,955	$	2,260	$	—

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	$	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	$	—	$	—

Nine Months Ended June 30, 2014:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	965,549	$	879,989	$	84,467	$	1,093
Cost of sales	$	515,612	$	463,492	$	52,120	$	—
Depreciation and amortization	$	43,985	$	40,733	$	3,252	$	—
Operating income	$	243,517	$	233,728	$	9,485	$	304
Interest expense	$	28,036	$	26,652	$	1,384	$	—
Income before income taxes	$	215,481	$	207,076	$	8,101	$	304
Capital expenditures	$	104,117	$	98,806	$	5,311	$	—
As of June 30, 2014
Total assets (at period end)	$	2,289,841	$	2,147,407	$	142,434	$	—
Goodwill (at period end)	$	182,145	$	182,145	$	—	$	—