The fair value of the letter of credit.

No definition available.

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

- Details

Name:	ora_Note22CommitmentsandContingenciesDetailsLineItems
Namespace Prefix:	ora_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage for royalty to be paid.

+ References

No definition available.

+ Details

Name:	ora_PercentageForRoyaltyToBePaid
Namespace Prefix:	ora_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The capped amount for royalty.

+ References

No definition available.

+ Details

Name:	ora_RoyaltyCapAmount
Namespace Prefix:	ora_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Royalty cap amount, increases based on the LIBOR rate.

+ References

No definition available.

+ Details

Name:	ora_RoyaltyCapAmountLIBORRate
Namespace Prefix:	ora_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308

+ Details

Name:	us-gaap_RecordedUnconditionalPurchaseObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_RoyaltyExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=ora_GeothermalResourceAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=ora_ConstructionInProcessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 22 - Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2003
Note 22 - Commitments and Contingencies (Details) [Line Items]
Royalty Expense	$ 0us-gaap_RoyaltyExpense	$ 0us-gaap_RoyaltyExpense	$ 0us-gaap_RoyaltyExpense
Letters of Credit Outstanding, Amount	353,100,000
Letter Of Credit Fair Value Disclosure	0ora_LetterOfCreditFairValueDisclosure
Recorded Unconditional Purchase Obligation	119,200,000
Royalty Cap Amount	1,600,000ora_RoyaltyCapAmount	1,500,000ora_RoyaltyCapAmount
Royalty Cap Amount LIBOR Rate	600,000ora_RoyaltyCapAmountLIBORRate	500,000ora_RoyaltyCapAmountLIBORRate
Operating Leases, Rent Expense	300,000us-gaap_LeaseAndRentalExpense	400,000us-gaap_LeaseAndRentalExpense	400,000us-gaap_LeaseAndRentalExpense
Geothermal Resource Agreement [Member]
Note 22 - Commitments and Contingencies (Details) [Line Items]
Royalty Expense	16,304,000	13,896,000	12,048,000
Minimum [Member]
Note 22 - Commitments and Contingencies (Details) [Line Items]
Percentage For Royalty To Be Paid				3.50%
Maximum [Member]
Note 22 - Commitments and Contingencies (Details) [Line Items]
Percentage For Royalty To Be Paid				5.00%
Construction In Process [Member]
Note 22 - Commitments and Contingencies (Details) [Line Items]
Recorded Unconditional Purchase Obligation	$ 44,100,000