Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue:
Electricity	$ 90,926	$ 91,692	$ 180,879	$ 186,509
Product	49,561	35,911	79,839	83,530
Total revenue	140,487	127,603	260,718	270,039
Cost of revenue:
Electricity	62,522	67,322	118,103	124,356
Product	27,182	20,324	47,807	52,267
Total cost of revenue	89,704	87,646	165,910	176,623
Gross margin	50,783	39,957	94,808	93,416
Operating expenses:
Research and development expenses	414	232	777	145
Selling and marketing expenses	4,283	3,216	7,716	6,595
General and administrative expenses	7,443	6,072	17,647	13,668
Write-off of unsuccessful exploration activities		8,107	174	8,107
Operating income	38,643	22,330	68,494	64,901
Other income (expense):
Interest income	44	90	53	201
Interest expense, net	(18,859)	(22,072)	(36,687)	(42,590)
Foreign currency translation and transaction losses	(571)	(55)	(1,937)	(693)
Income attributable to sale of tax benefits	4,731	6,130	10,283	12,847
Gain from sale of property, plant and equipment		7,628	(531)	7,628
Other non-operating income (expense), net	(1,675)	343	(1,392)	406
Income before income taxes and equity in losses of investees	22,313	14,394	38,814	42,700
Income tax provision	(6,056)	(4,967)	(11,515)	(11,287)
Equity in losses of investees, net	(984)	(114)	(1,759)	(311)
Net income	15,273	9,313	25,540	31,102
Net income attributable to noncontrolling interest	(859)	(177)	(1,094)	(414)
Net income attributable to the Company's stockholders	14,414	9,136	24,446	30,688
Comprehensive income:
Net income	15,273	9,313	25,540	31,102
Other comprehensive income (loss), net of related taxes:
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment	3,460	(4,088)	164	(4,088)
Loss in respect of derivative instruments designated for cash flow hedge	23		46
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge	(31)	(36)	(61)	(72)
Comprehensive income	18,725	5,189	25,689	26,942
Comprehensive income attributable to noncontrolling interest	(859)	(177)	(1,094)	(414)
Comprehensive income attributable to the Company's stockholders	$ 17,866	$ 5,012	$ 24,595	$ 26,528
Basic:
Net income (in Dollars per share)	$ 0.29	$ 0.20	$ 0.51	$ 0.67
Diluted:
Net income (in Dollars per share)	$ 0.28	$ 0.20	$ 0.49	$ 0.67
Weighted average number of shares used in computation of earnings per share attributable to the Company's stockholders:
Basic (in Shares)	48,881	45,606	48,063	45,545
Diluted (in Shares)	50,600	45,963	49,444	45,827
Dividend per share declared (in Dollars per share)	$ 0.06	$ 0.05	$ 0.12	$ 0.11