Consolidation and Nature of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash paid during the period for:
Income taxes, net of refunds	$ 1	$ 0
Interest, net of amounts capitalized	63,764	56,026
Significant non-cash investing and financing activities:
Accrued capital expenditures	95,879	86,991
Right-of-use operating lease assets obtained in exchange for operating lease liabilities	2,293	0
APS
Cash paid during the period for:
Income taxes, net of refunds	0	0
Interest, net of amounts capitalized	61,387	54,873
Significant non-cash investing and financing activities:
Accrued capital expenditures	95,879	86,944
Right-of-use operating lease assets obtained in exchange for operating lease liabilities	$ 2,293	$ 0