Derivatives and Risk Management - Schedule of Energy Commodity Derivative Volumes (Details) frequency in Thousands, MWh in Thousands, MMBTU in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020 MWh MMBTU frequency	Dec. 31, 2019 MWh MMBTU
Purchase [Member] | Physical [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020	29	2
2021	0	0
2022	0	0
2023	0	0
2024	0	0
Thereafter	0	0
Purchase [Member] | Physical [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020 | MMBTU	9,325	9,813
2021 | MMBTU	5,480	153
2022 | MMBTU	450	225
2023 | MMBTU	0	0
2024 | MMBTU	0	0
Thereafter | MMBTU	0	0
Purchase [Member] | Financial [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020	329	442
2021	123	0
2022	0	0
2023	0	0
2024	0	0
Thereafter	0	0
Purchase [Member] | Financial [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020 | MMBTU	54,560	78,803
2021 | MMBTU	46,425	25,523
2022 | MMBTU	11,300	4,725
2023 | MMBTU	900	0
2024 | MMBTU	0	0
Thereafter | MMBTU	0	0
Sales [Member] | Physical [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020	71	133
2021	0	0
2022	0	0
2023	0	0
2024	0	0
Thereafter	0	0
Sales [Member] | Physical [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020 | MMBTU	1,441	2,984
2021 | MMBTU	1,940	1,040
2022 | MMBTU	0	0
2023	0	0
2024	0	0
Thereafter | MMBTU	0	0
Sales [Member] | Financial [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020	802	1,724
2021	246	246
2022	0	0
2023	0	0
2024	0	0
Thereafter	0	0
Sales [Member] | Financial [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
2020 | MMBTU	21,460	37,848
2021 | MMBTU	30,745	13,108
2022 | MMBTU	4,500	675
2023 | MMBTU	0	0
2024	0	0
Thereafter | MMBTU	0	0