Note 9 - Business Segments (Tables)

9 Months Ended

Sep. 30, 2017

Notes Tables

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	Electricity		Product		Consolidated
	(Dollars in thousands)
Three Months Ended September 30, 2017:
Net revenue from external customers	$	112,273	$	44,912	$	157,185
Intersegment revenue		—		28,248		28,248
Operating income		36,205		7,765		43,970
Segment assets at period end (1)		2,371,855		131,883		2,503,738
Three Months Ended September 30, 2016:
Net revenue from external customers	$	109,795	$	74,822		184,617
Intersegment revenue		—		14,835		14,835
Operating income		23,903		24,320		48,223
Segment assets at period end		2,137,845		141,426		2,279,271
Nine Months Ended September 30, 2017:
Net revenues from external customers	$	339,826	$	186,621		526,447
Intersegment revenues		—		61,026		61,026
Operating income		113,220		43,398		156,618
Segment assets at period end (1)		2,371,855		131,883		2,503,738
Nine Months Ended September 30, 2016:
Net revenues from external customers	$	321,664	$	174,408		496,072
Intersegment revenues		—		36,042		36,042
Operating income		91,502		59,151		150,653
Segment assets at period end		2,137,845		141,426		2,279,271

Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]

	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
Revenue:
Total segment revenue	$	157,185		$	184,617		$	526,447		$	496,072
Intersegment revenue		28,248			14,835			61,026			36,042
Elimination of intersegment revenue		(28,248	)		(14,835	)		(61,026	)		(36,042	)
Total consolidated revenue	$	157,185		$	184,617		$	526,447		$	496,072
Operating income:
Operating income	$	43,970		$	48,223		$	156,618		$	150,653
Interest income		255			266			861			831
Interest expense, net		(11,692	)		(17,137	)		(41,155	)		(51,561	)
Derivatives and foreign currency transaction gains (losses)		(1,001	)		(222	)		2,040			(2,592	)
Income attributable to sale of tax benefits		3,506			3,463			14,019			12,380
Other non-operating expense, net		(1,592	)		(5,546	)		(1,678	)		(5,306	)
Total consolidated income before income taxes and equity in losses of investees	$	33,446		$	29,047		$	130,705		$	104,405