Number of options rolled by the Company.

No definition available.

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Namespace Prefix:	ora_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:energyItemType
Balance Type:	na
Period Type:	duration

- Definition

The strike price on the price risk option contract such as a put option or a call option.

+ References

No definition available.

+ Details

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Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow for derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow provided by derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

+ Details

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

- Definition

Specified interest rate, security price, commodity price, foreign exchange rate, index of prices or rates for a derivative contract measured in energy volume but not the derivative contract itself.

+ References

No definition available.

+ Details

Name:	us-gaap_UnderlyingDerivativeEnergyMeasure
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Note 7 - Fair Value of Financial Instruments (Details Textual) BTU in Millions, $ in Millions						1 Months Ended
	Jan. 12, 2017 USD ($) BTU $ / BTU	Feb. 24, 2016 USD ($) Boe $ / Boe	Feb. 02, 2016 USD ($) BTU $ / BTU	May 14, 2015 BTU $ / item	Mar. 06, 2014 BTU $ / BTU	Mar. 31, 2016 Boe $ / Boe $ / item	Feb. 28, 2016 $ / Boe
Derivative, Number of Options Rolled						2
Henry Hub Natural Gas Future ("NG") Contracts [Member] \| Put Option [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| BTU	4.1
Derivative, Price Risk Option Strike Price \| $ / BTU	3
Payments for Derivative Instrument, Investing Activities \| $	$ 0.7
Henry Hub Natural Gas Future ("NG") Contracts [Member] \| Call Option [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| BTU			4.1
Derivative, Price Risk Option Strike Price \| $ / BTU			2
Proceeds from Derivative Instrument, Investing Activities \| $			$ 1.9
Brent Oil Future Contracts [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| Boe		185,000
Brent Oil Future Contracts [Member] \| Minimum [Member]
Derivative, Price Risk Option Strike Price		32.8
Brent Oil Future Contracts [Member] \| Maximum [Member]
Derivative, Price Risk Option Strike Price		35.5
Brent Oil Future Contracts [Member] \| Call Option [Member]
Proceeds from Derivative Instrument, Investing Activities \| $		$ 1.1
Rolled Two Existing Options [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| Boe						31,800
Rolled Two Existing Options [Member] \| Minimum [Member]
Derivative, Price Risk Option Strike Price						41
Rolled Two Existing Options [Member] \| Maximum [Member]
Derivative, Price Risk Option Strike Price						42.5
Before Rolling Two Existing Options [Member] \| Minimum [Member]
Derivative, Price Risk Option Strike Price							32.8
Before Rolling Two Existing Options [Member] \| Maximum [Member]
Derivative, Price Risk Option Strike Price							33.5
Short Risk Reversal Transactions, Rolling Existing Call Option 1 [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| Boe						16,500
Short Risk Reversal Transactions, Rolling Existing Call Option 1 [Member] \| Minimum [Member]
Derivative, Price Risk Option Strike Price \| $ / item						28.5
Short Risk Reversal Transactions, Rolling Existing Call Option 1 [Member] \| Maximum [Member]
Derivative, Price Risk Option Strike Price \| $ / item						37.5
Short Risk Reversal Transactions, Rolling Existing Call Option 2 [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| Boe						17,000
Short Risk Reversal Transactions, Rolling Existing Call Option 2 [Member] \| Minimum [Member]
Derivative, Price Risk Option Strike Price \| $ / item						28
Short Risk Reversal Transactions, Rolling Existing Call Option 2 [Member] \| Maximum [Member]
Derivative, Price Risk Option Strike Price \| $ / item						38.5
NGI Swap Contract [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure \| BTU				2.4	2.2
Underlying, Derivative Energy Measure				3	4.95