Regulatory Matters - Summary of Utilities Rate Plans (RECO) (Details) - RECO - USD ($) $ in Millions	1 Months Ended		35 Months Ended
	Feb. 29, 2020	Jan. 31, 2016	Jan. 31, 2020
Electric
Public Utilities, General Disclosures [Line Items]
Plan electric system storm hardening amount		$ 15.7
Plan period (years)		3 years
Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities			$ 0.2
Regulatory liabilities, amortization period			3 years
Amortization to income of net regulatory assets	$ 4.8		$ 25.6
Regulatory assets, amortization period	4 years		4 years
Average rate base	$ 229.9		$ 178.7
Weighted average cost of capital (after-tax) (percent)	7.11%		7.47%
Authorized return on common equity (percent)	9.50%		9.60%
Cost of long-term debt (percent)	4.88%		5.37%
Common equity ratio (percent)	48.32%		49.70%
Scenario, Forecast | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ 12.0		$ 1.7
Actual return on common equity (percent)			7.50%
Scenario, Forecast | Year 2
Public Utilities, General Disclosures [Line Items]
Actual return on common equity (percent)			5.70%