Segment Information (Tables)

6 Months Ended

Mar. 31, 2014

Segment Reporting [Abstract]

Segment Information

No single customer represents more than ten percent of our consolidated revenues and there are no significant intersegment transactions. In addition, all of our reportable segments’ revenues are derived from sources within the United States and all of our reportable segments’ long-lived assets are located in the United States.

Financial information by business segment follows:

Three Months Ended March 31, 2014:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	513,956	$	480,163	$	33,552	$	241
Cost of sales	$	300,424	$	278,748	$	21,676	$	—
Depreciation and amortization	$	14,643	$	13,575	$	1,068	$	—
Operating income	$	137,954	$	134,560	$	3,492	$	(98	)
Interest expense	$	8,806	$	8,362	$	444	$	—
Income before income taxes	$	129,148	$	126,198	$	3,048	$	(98	)
Total assets (at period end)	$	2,340,617	$	2,195,437	$	145,180	$	—
Goodwill (at period end)	$	182,145	$	182,145	$	—	$	—
Capital expenditures	$	31,648	$	30,039	$	1,609	$	—

Three Months Ended March 31, 2013:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	395,901	$	368,635	$	26,951	$	315
Cost of sales	$	212,785	$	196,742	$	16,043	$	—
Depreciation and amortization	$	13,712	$	12,731	$	981	$	—
Operating income	$	109,230	$	105,749	$	3,389	$	92
Interest expense	$	9,820	$	9,327	$	493	$	—
Income before income taxes	$	99,410	$	96,422	$	2,896	$	92
Total assets (at period end)	$	2,348,337	$	2,184,816	$	163,521	$	—
Goodwill (at period end)	$	182,145	$	182,145	$	—	$	—
Capital expenditures	$	25,791	$	24,430	$	1,361	$	—

Six Months Ended March 31, 2014:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	812,855	$	751,725	$	60,513	$	617
Cost of sales	$	452,289	$	414,235	$	38,054	$	—
Depreciation and amortization	$	29,093	$	26,959	$	2,134	$	—
Operating income	$	223,797	$	216,613	$	7,181	$	3
Interest expense	$	17,603	$	16,748	$	855	$	—
Income before income taxes	$	206,194	$	199,865	$	6,326	$	3
Total assets (at period end)	$	2,340,617	$	2,195,437	$	145,180	$	—
Goodwill (at period end)	$	182,145	$	182,145	$	—	$	—
Capital expenditures	$	65,902	$	62,851	$	3,051	$	—

Six Months Ended March 31, 2013:

			Reportable Segments
	Total		Gas Utility		Electric Utility		Other
Revenues	$	669,698	$	616,889	$	52,069	$	740
Cost of sales	$	351,062	$	320,316	$	30,746	$	—
Depreciation and amortization	$	27,283	$	25,336	$	1,947	$	—
Operating income	$	181,794	$	175,538	$	6,013	$	243
Interest expense	$	19,897	$	18,899	$	998	$	—
Income before income taxes	$	161,897	$	156,639	$	5,015	$	243
Total assets (at period end)	$	2,348,337	$	2,184,816	$	163,521	$	—
Goodwill (at period end)	$	182,145	$	182,145	$	—	$	—
Capital expenditures	$	55,519	$	52,949	$	2,570	$	—