Note 1 - General and Basis of Presentation (Details) (USD $)	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Note 1 - General and Basis of Presentation (Details) [Line Items]
Valuation Allowances and Reserves, Adjustments		$ 3,100,000				$ 32,700,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	40,000		47,000	124,000	140,000
Interest Expense	18,459,000		15,400,000	51,826,000	44,541,000
Income Tax Expense (Benefit)	5,201,000	(4,269,000)	1,088,000	15,028,000	10,148,000	(3,091,000)
Cash, Cash Equivalents, and Short-term Investments	35,435,000		37,524,000	35,435,000	37,524,000	66,628,000	99,886,000
Accounts Receivable, Net, Current	60,526,000			60,526,000		55,680,000
Percentage of Total Accounts Receivables	62.00%			62.00%		45.00%
Southern California Edison Company [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Termination Fees		9,000,000
Contract Extension Period				6 years
Percentage Of Total Revenue	20.90%		20.40%	14.90%	19.20%
Sierra Pacific Power Company And Nevada Power Company [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Percentage Of Total Revenue	15.30%		14.50%	17.00%	14.20%
Kenya Power And Lighting Co Limited [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Percentage Of Total Revenue	13.80%		8.80%	10.90%	8.00%
Domestic Tax Authority [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Cash, Cash Equivalents, and Short-term Investments	14,065,000			14,065,000		41,231,000
Deposit Insurance Per Depositor (in Dollars per Item)	250,000			250,000
Foreign Tax Authority [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Cash, Cash Equivalents, and Short-term Investments	40,320,000			40,320,000		33,215,000
Accounts Receivable, Net, Current	23,272,000			23,272,000		17,606,000
Reclassification out of Accumulated Other Comprehensive Income [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Interest Expense	65,000		76,000	200,000	228,000
Income Tax Expense (Benefit)	25,000		29,000	76,000	88,000
Deferred Income Tax Charge [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Valuation Allowances and Reserves, Adjustments		3,100,000				6,600,000
Property, Plant and Equipment [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Valuation Allowances and Reserves, Adjustments						$ 26,100,000