Derivatives - Interest Rate Swaps (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024		Mar. 31, 2023		Dec. 31, 2023
Derivatives
Tax benefit (expense)		$ (0.9)		$ 0.4
Unrealized gain (loss) on designated cash flow hedge	[1]	3.0	[2]	(1.2)	[3]
Fair value of derivative assets—current		90.6				$ 76.9
Fair value of derivative assets—long-term		21.5				27.0
Fair value of derivative liabilities—current		(98.0)				(62.7)
Fair value of derivative liabilities—long-term		(21.8)				(26.7)
Interest income		1.5		0.5
Interest rate swap
Derivatives
Change in fair value of interest rate swap		3.9		(1.6)
Tax benefit (expense)		(0.9)		0.4
Unrealized gain (loss) on designated cash flow hedge		3.0		$ (1.2)
Fair value of derivative assets—current		4.3				3.3
Fair value of derivative assets—long-term		0.5				0.0
Fair value of derivative liabilities—long-term		0.0				(2.4)
Net fair value of commodity derivatives		4.8				0.9
Commodity swaps
Derivatives
Fair value of derivative assets—current		86.3				73.6
Fair value of derivative assets—long-term		21.0				27.0
Fair value of derivative liabilities—current		(98.0)				(62.7)
Fair value of derivative liabilities—long-term		(21.8)				(24.3)
Net fair value of commodity derivatives		$ (12.5)				$ 13.6

[1] Includes tax expense of $0.9 million and a tax benefit of $0.4 million for the three months ended March 31, 2024 and 2023, respectively.

[2] Includes tax expense of $0.9 million for the three months ended March 31, 2024.

[3] Includes a tax benefit of $0.4 million for the three months ended March 31, 2023.