Note 8 - Fair Value Measurements (Tables)

3 Months Ended

Dec. 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 December 31, 2023
ASSETS
Gas Utility:
U.S. stock/bond mutual funds	$	22.0	$	—	$	—		$	22.0
NYMEX/ICE natural gas contracts		4.7		—		(4.7	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		13.2		—		(13.2	)		—
Natural gas commodity contracts		—		45.5		(1.4	)		44.1
Other:
U.S. stock/bond mutual funds		14.6		—		—			14.6
U.S. bonds		21.6		—		—			21.6
Global bonds		1.4		—		—			1.4
Interest rate swaps		—		22.7		—			22.7
Total	$	77.5	$	68.2	$	(19.3	)	$	126.4
LIABILITIES
Gas Utility:
NYMEX/ICE natural gas contracts	$	60.7	$	—	$	(60.7	)	$	—
Gasoline and heating oil contracts		—		0.4		(0.4	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		32.7		—		(32.7	)		—
Natural gas commodity contracts		—		24.5		(1.4	)		23.1
Other:
Interest rate swaps		—		2.0		—			2.0
Total	$	93.4	$	26.9	$	(95.2	)	$	25.1

	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, 2023
ASSETS
Gas Utility:
U.S. stock/bond mutual funds	$	20.4	$	—	$	—		$	20.4
NYMEX/ICE natural gas contracts		6.3		—		(6.3	)		—
Gasoline and heating oil contracts		—		0.1		(0.1	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		10.1		—		(10.1	)		—
Natural gas commodity contracts		—		36.7		(3.6	)		33.1
Other:
U.S. stock/bond mutual funds		37.6		—		—			37.6
Interest rate swaps		—		44.2		—			44.2
Total	$	74.4	$	81.0	$	(20.1	)	$	135.3
LIABILITIES
Gas Utility:
NYMEX/ICE natural gas contracts	$	50.8	$	—	$	(44.0	)	$	6.8
Gas Marketing:
NYMEX/ICE natural gas contracts		21.8		—		(21.8	)		—
Natural gas commodity contracts		—		27.6		(3.6	)		24.0
Total	$	72.6	$	27.6	$	(69.4	)	$	30.8
As of December 31, 2022
ASSETS
Gas Utility:
U.S. stock/bond mutual funds	$	19.5	$	—	$	—		$	19.5
NYMEX/ICE natural gas contracts		0.4		—		(0.4	)		—
Gasoline and heating oil contracts		0.2		—		(0.2	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		52.0		—		(52.0	)		—
Natural gas commodity contracts *		—		92.9		(13.2	)		79.7
Other:
U.S. stock/bond mutual funds		28.3		—		—			28.3
Interest rate swaps *		—		61.4		—			61.4
Total	$	100.4	$	154.3	$	(65.8	)	$	188.9
LIABILITIES
Gas Utility:
NYMEX/ICE natural gas contracts	$	35.7	$	—	$	(35.7	)	$	—
Gasoline and heating oil contracts		0.2		—		(0.2	)		—
Gas Marketing:
NYMEX/ICE natural gas contracts		58.4		—		(58.4	)		—
Natural gas commodity contracts *		—		71.1		(13.2	)		57.9
Other:
Interest rate swaps *		—		0.8		—			0.8
Total	$	94.3	$	71.9	$	(107.5	)	$	58.7

	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Effects of Netting and Cash Margin Receivables /Payables			Total
As of December 31, 2023
ASSETS
U.S. stock/bond mutual funds	$	22.0	$	—	$	—		$	22.0
NYMEX/ICE natural gas contracts		4.7		—		(4.7	)		—
Total	$	26.7	$	—	$	(4.7	)	$	22.0
LIABILITIES
NYMEX/ICE natural gas contracts	$	60.7	$	—	$	(60.7	)	$	—
Gasoline and heating oil contracts		—		0.4		(0.4	)		—
Total	$	60.7	$	0.4	$	(61.1	)	$	—
As of September 30, 2023
ASSETS
U.S. stock/bond mutual funds	$	20.4	$	—	$	—		$	20.4
NYMEX/ICE natural gas contracts		6.3		—		(6.3	)		—
Gasoline and heating oil contracts		—		0.1		(0.1	)		—
Total	$	26.7	$	0.1	$	(6.4	)	$	20.4
LIABILITIES
NYMEX/ICE natural gas contracts	$	50.8	$	—	$	(44.0	)	$	6.8
As of December 31, 2022
ASSETS
U.S. stock/bond mutual funds	$	19.5	$	—	$	—		$	19.5
NYMEX/ICE natural gas contracts		0.4		—		(0.4	)		—
Gasoline and heating oil contracts		0.2		—		(0.2	)		—
Total	$	20.1	$	—	$	(0.6	)	$	19.5
LIABILITIES
NYMEX/ICE natural gas contracts	$	35.7	$	—	$	(35.7	)	$	—
Gasoline and heating oil contracts		0.2		—		(0.2	)		—
Total	$	35.9	$	—	$	(35.9	)	$	—