Debt (Tables)

12 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Composition of Long-term Debt

Long-term debt comprises the following at September 30:

	2018			2017
Senior Notes:
4.12%, due September 2046	$	200,000		$	200,000
4.98%, due March 2044	175,000			175,000
4.12%, due October 2046	100,000			100,000
6.21%, due September 2036	100,000			100,000
2.95%, due June 2026	100,000			100,000
Medium-Term Notes:
7.25%, due November 2017	—			20,000
5.67%, due January 2018	—			20,000
6.50%, due August 2033	20,000			20,000
6.13%, due October 2034	20,000			20,000
Variable-rate term loan, due through October 2022	120,313			—
Capital lease obligations	6,817			—
Total long-term debt	842,130			755,000
Less: unamortized debt issuance costs	(4,134		)	(3,899		)
Less: current maturities	(9,001		)	(39,996		)
Total long-term debt due after one year	$	828,995		$	711,105