Note 4 - Unconsolidated Investments - Unconsolidated Investments Mainly in Power Plants (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Sarulla	$ (6,481)	$ (4,772)
Sarulla [Member]
Sarulla	$ 25,367	$ (11,081)

Represents the accumulated losses in excess of investments in an entity not consolidated.

No definition available.

Name:	ora_AccumulatedLossesOfUnconsolidatedCompanyInExcessOfInvestment
Namespace Prefix:	ora_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant