Note 10 - Long-term Debt and Credit Agreements (Details) - Long-Term Debt (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Limited recourse:
	$ 677,353	$ 632,901
Less current portion	(52,363)	(51,514)
Non current portion	624,990	581,387
Full recourse agreements:
Recourse debt	324,056	444,955
Less current portion	(39,416)	(28,875)
Non current portion	284,640	416,080
Loan Agreement with TCW [Member]
Non-recourse:
Non-recourse debt		31,509
Loan Agreement with OPIC [Member]
Non-recourse:
Non-recourse debt	282,620	299,946
Ormat Funding Corp [Member]
Non-recourse:
Non-recourse debt	67,206	90,840
Orcal Geothermal Inc [Member]
Non-recourse:
Non-recourse debt	55,050	66,156
OFC Two Senior Secured Notes [Member]
Non-recourse:
Non-recourse debt	272,477	144,450
Senior Unsecured Bonds Member
Full recourse agreements:
Recourse debt	250,289	250,596
Institutional Investors [Member]
Full recourse agreements:
Recourse debt	21,887	32,868
Olkaria III - DEG [Member]
Full recourse agreements:
Recourse debt	31,580	39,474
Commercial Bank [Member]
Full recourse agreements:
Recourse debt		10,000
Revolving Credit Lines With Commerical Banks [Member]
Full recourse agreements:
Recourse debt	$ 20,300	$ 112,017