Derivatives - Interest Rate Swaps (Details) - USD ($)	3 Months Ended										9 Months Ended
	Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020		Sep. 30, 2019		Jun. 30, 2019		Sep. 30, 2020		Sep. 30, 2019		Dec. 31, 2019	Apr. 30, 2019
Derivatives
Derivative, notional amount																$ 850,000,000.0
Derivative, fixed interest rate																2.28%
Income tax (benefit) expense	$ 1,100,000	[1]	$ 500,000		$ (4,000,000.0)		$ (500,000)		$ (3,600,000)		$ (2,400,000)		$ (4,100,000)
(Loss) gain on designated cash flow hedge	3,600,000	[1],[2]	$ 1,500,000	[3]	$ (13,100,000)	[4]	(1,300,000)	[1],[5]	$ (9,900,000)	[6]	(8,000,000.0)	[1]	(11,200,000)	[1]
(Loss) gain on interest rate swaps	4,600,000						(100,000)				9,600,000		(400,000)
Interest expense expected to be reclassified out of accumulated other comprehensive income (loss) over the next twelve months	18,600,000										18,600,000
Fair value of derivative liabilities—current	(33,100,000)										(33,100,000)				$ (14,400,000)
Fair value of derivative liabilities—long-term	(4,500,000)										(4,500,000)				(6,800,000)
Interest rate swaps
Derivatives
Change in fair value of derivatives	4,700,000						$ (1,800,000)				(10,400,000)		$ (15,300,000)
Fair value of derivative liabilities—current	(18,500,000)										(18,500,000)				(5,600,000)
Fair value of derivative liabilities—long-term	(4,500,000)										(4,500,000)				(6,800,000)
Net fair value of commodity swaps	$ (23,000,000.0)										$ (23,000,000.0)				$ (12,400,000)

[1] Includes a tax expense of $1.1 million and a tax benefit of $2.4 million for the three and nine months ended September 30, 2020, respectively, and a tax benefit of $0.5 million and $4.1 million for the three and nine months ended September 30, 2019, respectively.

[2] Includes a tax expense of $1.1 million.

[3] Includes a tax expense of $0.5 million.

[4] Includes a tax benefit of $4.0 million.

[5] Includes a tax benefit of $0.5 million.

[6] Includes a tax benefit of $3.6 million.