Energy Purchase Contracts (Tables)

12 Months Ended

Dec. 31, 2019

Energy Purchase Contracts [Line Items]

Schedule of Utility Total Expenses

	2019		2018		2017
Utility power resources	$	376,769	$	357,656	$	380,523

Future Contractual Commitments for Power Resources and Natural Gas Resources

	2020		2021		2022		2023		2024		Thereafter		Total
Power resources	$	178,546	$	180,417	$	179,020	$	179,640	$	157,620	$	1,172,072	$	2,047,315
Natural gas resources	68,232		50,062		43,577		39,493		36,640		274,302		512,306
Total	$	246,778	$	230,479	$	222,597	$	219,133	$	194,260	$	1,446,374	$	2,559,621

Contractual Obligations [Member]

Energy Purchase Contracts [Line Items]

Future Contractual Commitments for Power Resources and Natural Gas Resources

	2020		2021		2022		2023		2024		Thereafter		Total
Contractual obligations	$	33,116	$	34,081	$	24,645	$	25,190	$	28,585	$	191,873	$	337,490