Consolidated Statements Of Income And Earnings Reinvested In The Business (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
INCOME
Operating Revenues	$ 701,720	$ 551,115	$ 1,248,277	$ 992,275
Operating Expenses:
Purchased Gas	199,592	106,661	301,219	158,280
Property, Franchise and Other Taxes	27,717	23,987	52,219	46,768
Depreciation, Depletion and Amortization	91,245	84,342	179,823	167,462
Impairment of Oil and Gas Producing Properties	0	0	0	76,152
Total Operating Expenses	455,354	337,076	792,252	685,759
Gain on Sale of Timber Properties	0	0	0	51,066
Operating Income	246,366	214,039	456,025	357,582
Other Income (Expense):
Other Income (Deductions)	10,018	(10,875)	8,940	(13,051)
Interest Expense on Long-Term Debt	(30,079)	(48,820)	(60,209)	(81,076)
Other Interest Expense	(1,519)	(1,698)	(2,680)	(3,618)
Income Before Income Taxes	224,786	152,646	402,076	259,837
Income Tax Expense	57,458	40,210	102,356	69,627
Net Income Available for Common Stock	167,328	112,436	299,720	190,210
EARNINGS REINVESTED IN THE BUSINESS
Balance at Beginning of Period	1,281,963	1,028,844	1,191,175	991,630
Beginning Retained Earnings Unappropriated And Current Period Net Income	1,449,291	1,141,280	1,490,895	1,181,840
Dividends on Common Stock	(41,608)	(40,562)	(83,212)	(81,122)
Balance at March 31	$ 1,407,683	$ 1,100,718	$ 1,407,683	$ 1,100,718
Earnings Per Common Share, Basic:
Net Income Available for Common Stock (in dollars per share)	$ 1.83	$ 1.23	$ 3.28	$ 2.09
Earnings Per Common Share, Diluted:
Net Income Available for Common Stock (in dollars per share)	$ 1.82	$ 1.23	$ 3.26	$ 2.08
Weighted Average Common Shares Outstanding:
Used in Basic Calculation (shares)	91,444,638	91,163,291	91,354,488	91,084,620
Used in Diluted Calculation (shares)	92,064,711	91,645,679	92,047,467	91,581,918
Dividends Per Common Share:
Dividends Declared (in dollars per share)	$ 0.455	$ 0.445	$ 0.910	$ 0.890
Utility and Energy Marketing [Member]
INCOME
Operating Revenues	$ 369,092	$ 270,849	$ 605,776	$ 460,315
Operating Expenses:
Operation and Maintenance	53,476	52,058	100,120	96,944
Exploration and Production and Other [Member]
INCOME
Operating Revenues	261,676	220,281	505,957	412,316
Operating Expenses:
Operation and Maintenance	49,806	41,895	95,425	83,922
Pipeline and Storage and Gathering [Member]
INCOME
Operating Revenues	70,952	59,985	136,544	119,644
Operating Expenses:
Operation and Maintenance	$ 33,518	$ 28,133	$ 63,446	$ 56,231