Leases - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Total operating leases
2021	$ 4.5
2022	4.4
2023	4.5
2024	4.3
2025	3.8
Thereafter	24.5
Total minimum lease payments	46.0
Less: interest	(10.2)
Finance leases
2021	10.6
2022	5.4
2023	1.6
2024	1.6
2025	1.6
Therafter	130.3
Total minimum lease payments	151.1
Less: interest	(87.7)
Present value of minimum lease payments	63.4	$ 45.9
Less: short-term lease liabilities	(8.1)
Long-term lease liabilities	55.3
Total Liabilities
Total operating leases
Present value of minimum lease payments	35.8
Other Current Liabilities
Total operating leases
Less: short-term lease liabilities	(3.4)
Other Long-term Liabilities
Total operating leases
Long-term lease liabilities	32.4
Power Purchase Contract
Finance leases
2021	9.4
2022	4.2
2023	0.0
2024	0.0
2025	0.0
Therafter	0.0
Total minimum lease payments	13.6
Less: interest	(1.5)
Present value of minimum lease payments	12.1
Less: short-term lease liabilities	(8.1)
Long-term lease liabilities	4.0
Two Creeks
Finance leases
2021	0.2
2022	0.2
2023	0.2
2024	0.2
2025	0.2
Therafter	22.6
Total minimum lease payments	23.6
Less: interest	(15.7)
Present value of minimum lease payments	7.9
Less: short-term lease liabilities	0.0
Long-term lease liabilities	7.9
Badger Hollow I
Finance leases
2021	0.7
2022	0.7
2023	0.7
2024	0.7
2025	0.7
Therafter	52.7
Total minimum lease payments	56.2
Less: interest	(35.9)
Present value of minimum lease payments	20.3
Less: short-term lease liabilities	0.0
Long-term lease liabilities	20.3
Badger Hollow II
Finance leases
2021	0.3
2022	0.3
2023	0.7
2024	0.7
2025	0.7
Therafter	55.0
Total minimum lease payments	57.7
Less: interest	(34.6)
Present value of minimum lease payments	23.1
Less: short-term lease liabilities	0.0
Long-term lease liabilities	$ 23.1