Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Ormat Nevada ORTP LLC [Member] Common Stock [Member]	Ormat Nevada ORTP LLC [Member] Additional Paid-in Capital [Member]	Ormat Nevada ORTP LLC [Member] Retained Earnings [Member]	Ormat Nevada ORTP LLC [Member] AOCI Attributable to Parent [Member]	Ormat Nevada ORTP LLC [Member] Parent [Member]	Ormat Nevada ORTP LLC [Member] Noncontrolling Interest [Member]	Ormat Nevada ORTP LLC [Member]	OPC LLC [Member] Common Stock [Member]	OPC LLC [Member] Additional Paid-in Capital [Member]	OPC LLC [Member] Retained Earnings [Member]	OPC LLC [Member] AOCI Attributable to Parent [Member]	OPC LLC [Member] Parent [Member]	OPC LLC [Member] Noncontrolling Interest [Member]	OPC LLC [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2014															45,537
Balance at Dec. 31, 2014															$ 46	$ 742,006	$ 44,670	$ (9,221)	$ 777,501	$ 11,823	$ 789,324
Stock-based compensation																3,955			3,955		3,955
Exercise of options by employees and directors (in shares)															574
Exercise of options by employees and directors																6,085			6,085		6,085
Share exchange with Parent (in shares)															2,996
Share exchange with Parent															$ 3	26,012			26,015		26,015
Cash paid to noncontrolling interest																				(7,196)	(7,196)
Cash dividend declared																	(12,716)		(12,716)		(12,716)
Issuance of shares to noncontrolling interest, net of transaction costs																71,165			71,165	85,470	156,635
Net income																	120,372		120,372	3,776	124,148
Other comprehensive income (loss), net of related taxes:
Loss in respect of derivative instruments designated for cash flow hedge																		147	147		147
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment																		1,028	1,028		1,028
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																		(118)	(118)		(118)
Stock-based compensation																3,955			3,955		3,955
Exercise of options by employees and directors (in shares)															574
Exercise of options by employees and directors																6,085			6,085		6,085
Cash paid to noncontrolling interest																				(7,196)	(7,196)
Cash dividend declared																	(12,716)		(12,716)		(12,716)
Issuance of shares to noncontrolling interest, net of transaction costs																71,165			71,165	85,470	156,635
Net income																	120,372		120,372	3,776	124,148
Currency translation adjustment
Balance (in shares) at Dec. 31, 2015															49,107
Balance at Dec. 31, 2015															$ 49	849,223	152,326	(8,164)	993,434	93,873	1,087,307
Stock-based compensation																5,157			5,157		5,157
Exercise of options by employees and directors (in shares)															560
Exercise of options by employees and directors															$ 1	7,249			7,250		7,250
Cash paid to noncontrolling interest																				(57,391)	(57,391)
Cash dividend declared																	(25,682)		(25,682)		(25,682)
Issuance of shares to noncontrolling interest, net of transaction costs																7,834			7,834	36,268	44,102
Net income																	88,708		88,708	7,302	96,010
Other comprehensive income (loss), net of related taxes:
Loss in respect of derivative instruments designated for cash flow hedge																		141	141		141
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment																		1,185	1,185		1,185
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																		(96)	(96)		(96)
Stock-based compensation																5,157			5,157		5,157
Exercise of options by employees and directors (in shares)															560
Exercise of options by employees and directors															$ 1	7,249			7,250		7,250
Cash paid to noncontrolling interest																				(57,391)	(57,391)
Cash dividend declared																	(25,682)		(25,682)		(25,682)
Increase in noncontrolling interest in Guadeloupe																				8,240	8,240
Increase in noncontrolling interest in Opal Geo																				3,697	3,697
Issuance of shares to noncontrolling interest, net of transaction costs																7,834			7,834	36,268	44,102
Net income																	88,708		88,708	7,302	96,010
Currency translation adjustment																		(1,241)	(1,241)	(407)	(1,648)
Balance (in shares) at Dec. 31, 2016															49,667
Balance at Dec. 31, 2016															$ 50	869,463	215,352	(8,175)	1,076,690	91,582	1,168,272
Stock-based compensation																8,760			8,760		8,760
Exercise of options by employees and directors (in shares)															942
Exercise of options by employees and directors															$ 1	16,111			16,112		16,112
Cash paid to noncontrolling interest																				(21,313)	(21,313)
Cash dividend declared																	(20,511)		(20,511)		(20,511)
Net income																	132,414		132,414	13,643	146,057
Other comprehensive income (loss), net of related taxes:
Loss in respect of derivative instruments designated for cash flow hedge																		135	135		135
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment																		804	804		804
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																		(73)	(73)		(73)
Stock-based compensation																8,760			8,760		8,760
Exercise of options by employees and directors (in shares)															942
Exercise of options by employees and directors															$ 1	16,111			16,112		16,112
Cash paid to noncontrolling interest																				(21,313)	(21,313)
Cash dividend declared																	(20,511)		(20,511)		(20,511)
Net income																	132,414		132,414	13,643	146,057
Currency translation adjustment																		2,603	2,603	837	3,440
Buyout of Class B membership		$ 2,913			$ 2,913	$ (6,964)	$ (4,051)		$ (8,469)			$ (8,469)	$ 6,537	$ (1,932)
Balance (in shares) at Dec. 31, 2017															50,609
Balance at Dec. 31, 2017															$ 51	$ 888,778	$ 327,255	$ (4,706)	$ 1,211,378	$ 84,322	$ 1,295,700