Depreciation and Amortization, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 30,449	$ 16,532	$ 92,428	$ 46,000
Electricity Operating Segment [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization	6,008	6,687	18,952	17,772
Gas Operating Segment [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization	4,363	5,084	12,819	13,831
Water Operating Segment [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization	3,824	3,860	11,941	11,706
Networks Operating Segment [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization	15,214	0	45,449	0
Corporate Unallocated [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 1,040	$ 901	$ 3,267	$ 2,691