CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Electricity	$ 86,815	$ 83,357	$ 246,273	$ 218,269
Product	24,026	18,120	67,002	62,128
Total revenues	110,841	101,477	313,275	280,397
Cost of revenues:
Electricity	57,941	61,530	186,090	179,551
Product	17,137	14,764	43,276	41,316
Total cost of revenues	75,078	76,294	229,366	220,867
Gross margin	35,763	25,183	83,909	59,530
Operating expenses:
Research and development expenses	2,346	1,252	7,128	8,133
Selling and marketing expenses	2,940	3,333	9,325	9,221
General and administrative expenses	6,269	5,780	20,755	19,796
Write-off of unsuccessful exploration activities				3,050
Operating income	24,208	14,818	46,701	19,330
Other income (expense):
Interest income	438	140	1,289	432
Interest expense, net	(23,909)	(10,961)	(54,431)	(30,101)
Foreign currency translation and transaction gains (losses)	(2,659)	1,074	(1,546)	475
Income attributable to sale of tax benefits	2,344	2,183	7,624	6,392
Gain on acquisition of controlling interest		36,928		36,928
Other non-operating income (expense), net	347	233	465	(47)
Income from continuing operations, before income taxes and equity in income (losses) of investees	769	44,415	102	33,409
Income tax benefit (expense)	305	(11,931)	726	(6,009)
Equity in income (losses) of investees, net	(71)	(83)	(552)	942
Income from continuing operations	1,003	32,401	276	28,342
Discontinued operations:
Income from discontinued operations, net of related tax of $0, $0, $0 and $6, respectively				14
Gain on sale of a subsidiary in New Zealand, net of related tax of $0, $0, $0 and $2,000, respectively				4,336
Net income	1,003	32,401	276	32,692
Net (income) loss attributable to noncontrolling interest	(137)	58	(252)	168
Net income attributable to the Company's stockholders	866	32,459	24	32,860
Comprehensive income (loss):
Net income	1,003	32,401	276	32,692
Other comprehensive income (loss), net of related taxes:
Currency translation adjustment				43
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge	(53)	(61)	(159)	(177)
Change in unrealized gains or losses on marketable securities available-for-sale	(111)		(320)	(80)
Comprehensive income (loss)	839	32,340	(203)	32,478
Comprehensive (income) loss attributable to noncontrolling interest	(137)	58	(252)	168
Comprehensive income (loss) attributable to the Company's stockholders	$ 702	$ 32,398	$ (455)	$ 32,646
Earnings per share attributable to the Company's stockholders - basic and diluted:
Income from continuing operations	$ 0.02	$ 0.71	$ 0.00	$ 0.62
Discontinued operations				$ 0.10
Net income	$ 0.02	$ 0.71	$ 0.00	$ 0.72
Weighted average number of shares used in computation of earnings per share attributable to the Company's stockholders:
Basic	45,431	45,431	45,431	45,431
Diluted	45,440	45,450	45,442	45,452
Dividend per share declared	$ 0.04	$ 0.05	$ 0.13	$ 0.22