Note 1 - General and Basis of Presentation (Details) (USD $)	3 Months Ended		12 Months Ended		3 Months Ended										3 Months Ended			12 Months Ended		0 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Mar. 31, 2014 Southern California Edison Company [Member]	Mar. 31, 2013 Southern California Edison Company [Member]	Mar. 31, 2014 Sierra Pacific Power Company And Nevada Power Company [Member]	Mar. 31, 2013 Sierra Pacific Power Company And Nevada Power Company [Member]	Mar. 31, 2014 Kenya Power And Lighting Co Limited [Member]	Mar. 31, 2013 Kenya Power And Lighting Co Limited [Member]	Mar. 31, 2014 Domestic Tax Authority [Member]	Dec. 31, 2013 Domestic Tax Authority [Member]	Mar. 31, 2014 Foreign Tax Authority [Member]	Dec. 31, 2013 Foreign Tax Authority [Member]	Mar. 31, 2014 Reclassification out of Accumulated Other Comprehensive Income [Member]	Mar. 31, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member]	Mar. 31, 2013 Deferred Income Tax Charge [Member]	Dec. 31, 2012 Deferred Income Tax Charge [Member]	Dec. 31, 2012 Property, Plant and Equipment [Member]	Mar. 26, 2014 Heber Solar Project [Member]
Note 1 - General and Basis of Presentation (Details) [Line Items]
Valuation Allowances and Reserves, Adjustments		$ 3,100,000	$ 32,700,000														$ 3,100,000	$ 6,600,000	$ 26,100,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	36,000	42,000
Interest Expense	20,518,000	15,863,000													58,000	70,000
Income Tax Expense (Benefit)	6,320,000	(4,269,000)	(3,091,000)												22,000	28,000
Termination Fees						9,000,000
Contract Extension Period						6 years
Sales Price of Disposition																				35,250,000
Proceeds from Sales of Business, Affiliate and Productive Assets																				15,000,000
Gain (Loss) on Sale of Project																				7,500,000
Cash, Cash Equivalents, and Short-term Investments	47,927,000	57,627,000	66,628,000	57,354,000							11,476,000	13,805,000	49,438,000	56,133,000
Deposit Insurance Per Depositor (in Dollars per Item)											250,000
Accounts Receivable, Net, Current	$ 55,676,000			$ 95,365,000									$ 27,075,000	$ 32,231,000
Percentage of Total Accounts Receivables	68.30%			35.00%
Percentage Of Total Revenue					12.10%	11.70%	15.30%	15.50%	14.30%	8.40%