Equity Method Investment (Details) - NMRD $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) MW	Mar. 31, 2019 USD ($)
Business Acquisition [Line Items]
Renewable energy capacity in operating (in mw) | MW	85.1
PNMR Development
Business Acquisition [Line Items]
Ownership percentage	50.00%
Contribution to construction activities | $	$ 10.0	$ 7.0