Note 8 - Fair Value Measurements (Tables)

6 Months Ended

Mar. 31, 2023

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Effects of Netting and Cash Margin Receivables /Payables			Total
As of March 31, 2023
ASSETS
Gas Utility:
U.S. stock/bond mutual funds	$	20.7	$	—	$	—		$	20.7
NYMEX/ICE natural gas contracts		0.1		—		(0.1	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		31.9		—		(31.9	)		—
Natural gas commodity contracts		39.2		—		(1.3	)		37.9
Other:
U.S. stock/bond mutual funds		29.2		—		—			29.2
Interest rate swaps		16.5		—		—			16.5
Total	$	137.6	$	—	$	(33.3	)	$	104.3
LIABILITIES
Gas Utility:
NYMEX/ICE natural gas contracts	$	62.7	$	—	$	(62.7	)	$	—
Gasoline and heating oil contracts		0.5		—		(0.5	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		48.1		—		(48.1	)		—
Natural gas commodity contracts		32.4		—		(1.3	)		31.1
Other:
Interest rate swaps		2.2		—		—			2.2
Total	$	145.9	$	—	$	(112.6	)	$	33.3

	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Effects of Netting and Cash Margin Receivables /Payables			Total
As of September 30, 2022
ASSETS
Gas Utility:
U.S. stock/bond mutual funds	$	19.1	$	—	$	—		$	19.1
NYMEX/ICE natural gas contracts		57.8		—		(57.8	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		91.8		—		(91.8	)		—
Natural gas commodity contracts		56.6		—		(4.0	)		52.6
Other:
U.S. stock/bond mutual funds		29.3		—		—			29.3
Interest rate swaps		63.6		—		—			63.6
Total	$	318.2	$	—	$	(153.6	)	$	164.6
LIABILITIES
Gas Utility:
NYMEX/ICE natural gas contracts	$	30.7	$	—	$	(30.7	)	$	—
Gas Marketing:
NYMEX/ICE natural gas contracts		82.3		—		(82.3	)		—
Natural gas commodity contracts		65.5		—		(4.0	)		61.5
Total	$	178.5	$	—	$	(117.0	)	$	61.5
As of March 31, 2022
ASSETS
Gas Utility:
U.S. stock/bond mutual funds	$	23.0	$	—	$	—		$	23.0
NYMEX/ICE natural gas contracts		58.9		—		(58.9	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		96.1		—		(88.4	)		7.7
Natural gas commodity contracts		30.8		—		(1.0	)		29.8
Other:
U.S. stock/bond mutual funds		24.1		—		—			24.1
Interest rate swaps		28.8		—		(7.9	)		20.9
Total	$	261.7	$	—	$	(156.2	)	$	105.5
LIABILITIES
Gas Marketing:
NYMEX/ICE natural gas contracts	$	40.4	$	—	$	(40.4	)	$	—
Natural gas commodity contracts		106.2		—		(1.0	)		105.2
Other:
Interest rate swaps		7.9		—		(7.9	)		—
Total	$	154.5	$	—	$	(49.3	)	$	105.2

	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Effects of Netting and Cash Margin Receivables /Payables			Total
As of March 31, 2023
ASSETS
U.S. stock/bond mutual funds	$	20.7	$	—	$	—		$	20.7
NYMEX/ICE natural gas contracts		0.1		—		(0.1	)		—
Total	$	20.8	$	—	$	(0.1	)	$	20.7
LIABILITIES
NYMEX/ICE natural gas contracts	$	62.7	$	—	$	(62.7	)	$	—
Gasoline and heating oil contracts		0.5		—		(0.5	)		—
Total	$	63.2	$	—	$	(63.2	)	$	—
As of September 30, 2022
ASSETS
U.S. stock/bond mutual funds	$	19.1	$	—	$	—		$	19.1
NYMEX/ICE natural gas contracts		57.8		—		(57.8	)		—
Total	$	76.9	$	—	$	(57.8	)	$	19.1
LIABILITIES
NYMEX/ICE natural gas contracts	$	30.7	$	—	$	(30.7	)	$	—
As of March 31, 2022
ASSETS
U.S. stock/bond mutual funds	$	23.0	$	—	$	—		$	23.0
NYMEX/ICE natural gas contracts		58.9		—		(58.9	)		—
Total	$	81.9	$	—	$	(58.9	)	$	23.0