Business Segment Information (Tables)

6 Months Ended

Mar. 31, 2018

Segment Reporting [Abstract]

Financial Segment Information By Segment

Quarter Ended March 31, 2018 (Thousands)
	Exploration and Production	Pipeline and Storage	Gathering	Utility	Energy Marketing	Total Reportable Segments	All Other	Corporate and Intersegment Eliminations	Total Consolidated
Revenue from External Customers	$146,411	$53,714	$(99)	$283,778	$55,644	$539,448	$1,232	$225	$540,905
Intersegment Revenues	$—	$23,044	$27,832	$5,700	$(51)	$56,525	$—	$(56,525)	$—
Segment Profit: Net Income (Loss)	$26,537	$22,724	$11,770	$33,360	$578	$94,969	$207	$(3,329)	$91,847

Six Months Ended March 31, 2018 (Thousands)
	Exploration and Production	Pipeline and Storage	Gathering	Utility	Energy Marketing	Total Reportable Segments	All Other	Corporate and Intersegment Eliminations	Total Consolidated
Revenue from External Customers	$285,552	$107,025	$71	$470,867	$94,280	$957,795	$2,328	$438	$960,561
Intersegment Revenues	$—	$45,028	$51,497	$7,882	$76	$104,483	$—	$(104,483)	$—
Segment Profit: Net Income (Loss)	$133,235	$61,186	$57,169	$54,353	$1,624	$307,567	$(511)	$(16,555)	$290,501

(Thousands)	Exploration and Production	Pipeline and Storage	Gathering	Utility	Energy Marketing	Total Reportable Segments	All Other	Corporate and Intersegment Eliminations	Total Consolidated
Segment Assets:
At March 31, 2018	$1,540,251	$1,764,554	$517,335	$1,963,421	$61,166	$5,846,727	$77,252	$(9,406)	$5,914,573
At September 30, 2017	$1,407,152	$1,929,788	$580,051	$2,013,123	$60,937	$5,991,051	$76,861	$35,408	$6,103,320

Quarter Ended March 31, 2017 (Thousands)
	Exploration and Production	Pipeline and Storage	Gathering	Utility	Energy Marketing	Total Reportable Segments	All Other	Corporate and Intersegment Eliminations	Total Consolidated
Revenue from External Customers	$159,553	$53,163	$26	$257,949	$50,940	$521,631	$218	$226	$522,075
Intersegment Revenues	$—	$22,592	$27,936	$6,096	$16	$56,640	$—	$(56,640)	$—
Segment Profit: Net Income (Loss)	$33,769	$19,256	$10,285	$25,581	$905	$89,796	$(221)	$(291)	$89,284

Six Months Ended March 31, 2017 (Thousands)
	Exploration and Production	Pipeline and Storage	Gathering	Utility	Energy Marketing	Total Reportable Segments	All Other	Corporate and Intersegment Eliminations	Total Consolidated
Revenue from External Customers	$320,485	$106,164	$52	$428,919	$87,750	$943,370	$772	$434	$944,576
Intersegment Revenues	$—	$44,746	$55,776	$7,922	$35	$108,479	$—	$(108,479)	$—
Segment Profit: Net Income (Loss)	$68,849	$38,624	$21,266	$46,755	$2,687	$178,181	$(400)	$410	$178,191