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Capitalization (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands			9 Months Ended
	Jun. 03, 2020	Jun. 02, 2020	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019
Debt Instrument [Line Items]
Shares tendered			91,269
Current Portion of Long-Term Debt			$ 0		$ 0
Common Stock, Par Value			$ 1		$ 1
Net Proceeds from Issuance of Long-Term Debt			$ 493,108	$ 0
5.50% Notes Due January 15, 2026 [Member]
Debt Instrument [Line Items]
Long-Term Debt, face value	$ 500,000
Debt Instrument, Interest Rate, Stated Percentage	5.50%
Net Proceeds from Issuance of Long-Term Debt	$ 493,100
Percentage of Principal Amount	101.00%
Maximum interest rate adjustment	2.00%
5.50% Notes Due January 15, 2026 [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.50%
June 2, 2020 Public Offering of Common Stock [Member]
Debt Instrument [Line Items]
Common Stock, Par Value		$ 1.00
Proceeds from Issuance of Common Stock		$ 165,900
Common Stock Issued, Price Per Share		$ 39.50
Common Stock Issued from Sale of Common Stock (Shares)		4,370,000
Fourth Amended & Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			750,000
364-Day Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 200,000
Restricted Stock Units [Member]
Debt Instrument [Line Items]
Common stock issued			87,135
Performance Shares [Member]
Debt Instrument [Line Items]
Common stock issued			231,246
Board Of Directors [Member]
Debt Instrument [Line Items]
Common stock issued			31,253