Regulatory Matters - Summary of Utilities Rate Plans (RECO) (Details) - RECO - USD ($) $ in Millions	1 Months Ended			3 Months Ended	9 Months Ended	35 Months Ended
	Feb. 29, 2020	Apr. 30, 2017	Jan. 31, 2016	Mar. 31, 2017	Dec. 31, 2017	Jan. 31, 2020
Public Utilities, General Disclosures [Line Items]
Utilities operating expense, depreciation and amortization						$ 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)	711.00%					7.47%
Authorized return on common equity (percent)	950.00%					960.00%
Cost of long-term debt (percent)	488.00%					537.00%
Common Equity Ratio, Percentage	4832.00%					4970.00%
FERC
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount		$ 17.7		$ 11.8
Return on common equity (percent)					10.00%
Electric
Public Utilities, General Disclosures [Line Items]
Plan electric system storm hardening amount			$ 15.7
Plan period (years)			3 years
Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ 12.0					$ 1.7
Actual return on common equity (percent)	5.40%					7.50%
Year 2
Public Utilities, General Disclosures [Line Items]
Actual return on common equity (percent)						5.70%