Consolidation and Nature of Operations (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash paid (received) during the period for:
Income taxes, net of refunds	$ (788)	$ (3,028)
Interest, net of amounts capitalized	112,010	107,417
Significant non-cash investing and financing activities:
Accrued capital expenditures	105,515	87,815
Dividends accrued but not yet paid	93,610	88,066
APS
Cash paid (received) during the period for:
Income taxes, net of refunds	3,317	0
Interest, net of amounts capitalized	107,044	100,991
Significant non-cash investing and financing activities:
Accrued capital expenditures	105,515	87,815
Dividends accrued but not yet paid	$ 93,500	$ 88,000