Note 1 - General and Basis of Presentation (Tables)

6 Months Ended

Jun. 30, 2018

Notes Tables

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]

Cash and cash equivalents and restricted cash	$	37.9
Working capital		(8.2	)
Property, plant and equipment and construction-in-process		77.3
Intangible assets (1)		127.0
Deferred tax liability		(4.9	)
Long-term term debt, net of deferred transaction costs		(98.3	)
Asset retirement obligation		(9.0	)
Total identifiable assets and liabilities acquired	$	121.8
Goodwill (2)	$	19.3

Business Acquisition, Pro Forma Information [Table Text Block]

	Pro forma for the six months ended June 30, 2018		Pro forma for the six months ended June 30, 2017		Pro forma for the three months ended June 30, 2018		Pro forma for the three months ended June 30, 2017
	(Dollars in thousands)
Electricity revenues	$	265,965	$	241,420	$	125,003	$	117,207
Total revenues		373,619		384,010		181,123		185,675
Operating profit		89,219		114,753		36,200		53,238

Schedule of Cash and Cash Equivalents [Table Text Block]

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Cash and cash equivalents	$	66,696	$	47,818
Restricted cash and cash equivalents		76,041		48,825
Total Cash and cash equivalents and restricted cash and cash equivalents	$	142,737	$	96,643