Business Segments (Segment Financial Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
External customer revenues	$ 262.1	$ 188.2	$ 652.3	$ 511.5
Intersegment revenues	0.0	0.0	0.0	0.0
Total revenues	262.1	188.2	652.3	511.5
Depreciation and amortization	20.0	18.9	59.6	56.9
Interest expense	18.1	15.8	50.1	47.0
Total assets	2,253.0		2,253.0		$ 2,171.8
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(23.8)	7.7	(12.7)	23.1
Operating Segments [Member] | Utility [Member]
Segment Reporting Information [Line Items]
External customer revenues	259.7	185.9	645.0	504.2
Intersegment revenues	0.2	0.2	0.6	0.6
Total revenues	259.9	186.1	645.6	504.8
Depreciation and amortization	19.8	18.6	58.7	55.8
Interest expense	8.4	6.1	21.1	18.1
Total assets					2,162.6
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(15.6)	16.1	11.3	46.7
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
External customer revenues	2.4	2.3	7.3	7.3
Intersegment revenues	0.8	0.8	2.6	2.6
Total revenues	3.2	3.1	9.9	9.9
Depreciation and amortization	0.2	0.3	0.9	1.1
Interest expense	9.7	9.7	29.0	28.9
Total assets	18.3		18.3		9.2
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(8.2)	(8.4)	(24.0)	(23.6)
Intersegment Eliminations
Segment Reporting Information [Line Items]
External customer revenues	0.0	0.0	0.0	0.0
Intersegment revenues	(1.0)	(1.0)	(3.2)	(3.2)
Total revenues	(1.0)	(1.0)	(3.2)	(3.2)
Depreciation and amortization	0.0	0.0	0.0	0.0
Interest expense	0.0	0.0	0.0	0.0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	0.0	0.0	0.0	0.0
Subsidiaries [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	19.8	18.6	58.7	55.8
Interest expense	8.4	6.1	21.1	18.1
Total assets	2,234.7		2,234.7		$ 2,162.6
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ (15.6)	$ 16.1	$ 11.3	$ 46.7