v3.8.0.1
Nature of the business, Concessional assets owned (Details) - USD ($)
$ in Thousands
 12 Months Ended
Jan. 07, 2016
Sep. 30, 2013
Dec. 31, 2017
Dec. 31, 2016
ACT [Member]        
Nature of the business [Abstract]        
Type     Efficient natural gas  
Ownership     100.00%  
Location     Mexico  
Currency [1]     USD  
Capacity (gross)     300 MW  
Counterparty credit ratings [2]     BBB+/A3/BBB+  
COD [3]     2Q 2013  
Contract years left [4]     15 years  
ATN [Member]        
Nature of the business [Abstract]        
Type     Transmission line  
Ownership     100.00%  
Location     Peru  
Currency [1]     USD  
Capacity (gross)     362 miles  
Counterparty credit ratings [2]     BBB+/A3/BBB+  
COD [3]     1Q 2011  
Contract years left [4]     23 years  
ATS [Member]        
Nature of the business [Abstract]        
Type     Transmission line  
Ownership     100.00%  
Location     Peru  
Currency [1]     USD  
Capacity (gross)     569 miles  
Counterparty credit ratings [2]     BBB+/A3/BBB+  
COD [3]     1Q 2014  
Contract years left [4]     26 years  
ATN2 [Member]        
Nature of the business [Abstract]        
Type     Transmission line  
Ownership     100.00%  
Location     Peru  
Currency [1]     USD  
Capacity (gross)     81 miles  
Counterparty credit ratings [2]     Not rated  
COD [3]     2Q 2015  
Contract years left [4]     15 years  
Quadra 1 [Member]        
Nature of the business [Abstract]        
Type     Transmission line  
Ownership     100.00%  
Location     Chile  
Currency [1]     USD  
Capacity (gross)     49 miles  
Counterparty credit ratings [2]     Not rated  
COD [3]     2Q 2014  
Contract years left [4]     17 years  
Quadra 2 [Member]        
Nature of the business [Abstract]        
Type     Transmission line  
Ownership     100.00%  
Location     Chile  
Currency [1]     USD  
Capacity (gross)     32 miles  
Counterparty credit ratings [2]     Not rated  
COD [3]     1Q 2014  
Contract years left [4]     17 years  
Palmucho [Member]        
Nature of the business [Abstract]        
Type     Transmission line  
Ownership     100.00%  
Location     Chile  
Currency [1]     USD  
Capacity (gross)     6 miles  
Counterparty credit ratings [2]     BBB+/Baa2/BBB+  
COD [3]     4Q 2007  
Contract years left [4]     20 years  
Skikda [Member]        
Nature of the business [Abstract]        
Type     Water  
Ownership [5]     34.20%  
Location     Algeria  
Currency [1]     USD  
Capacity (gross)     3.5 M ft3/day  
Counterparty credit ratings [2]     Not rated  
COD [3]     1Q 2009  
Contract years left [4]     16 years  
Skikda [Member] | Algerian Energy Company, SPA [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     49.00%  
Skikda [Member] | Valoriza Agua, S.L. [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     16.83%  
Honaine [Member]        
Nature of the business [Abstract]        
Type     Water  
Ownership [6]     25.50%  
Location     Algeria  
Currency [1]     USD  
Capacity (gross)     7 M ft3/day  
Counterparty credit ratings [2]     Not rated  
COD [3]     3Q 2012  
Contract years left [4]     20 years  
Honaine [Member] | Algerian Energy Company, SPA [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     49.00%  
Honaine [Member] | Valoriza Agua, S.L. [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     25.50%  
PS10/PS20 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     31 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     1Q 2007 & 2Q 2009  
PS10 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     14 years  
PS20 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     16 years  
Solana [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Ownership interest type [7]     Class B  
Location     Arizona (USA)  
Currency [1]     USD  
Capacity (gross)     280 MW  
Counterparty credit ratings [2]     A-/A3/A-  
COD [3]     4Q 2013  
Contract years left [4]     26 years  
Solana [Member] | Liberty Interactive Corporation [Member]        
Nature of the business [Abstract]        
Class A membership investment   $ 300,000    
Percentage of dividends and taxable loss once certain conditions met   22.60%    
Solana [Member] | Liberty Interactive Corporation [Member] | Bottom of Range [Member]        
Nature of the business [Abstract]        
Percentage of dividends and taxable loss received   54.06%    
Solana [Member] | Liberty Interactive Corporation [Member] | Top of Range [Member]        
Nature of the business [Abstract]        
Percentage of dividends and taxable loss received   61.20%    
Mojave [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Location     California (USA)  
Currency [1]     USD  
Capacity (gross)     280 MW  
Counterparty credit ratings [2]     A-/A3/A-  
COD [3]     4Q 2014  
Contract years left [4]     22 years  
Solaben 2 & 3 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership [8]     70.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     2x50 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     3Q 2012 & 2Q 2012  
Solaben 2 & 3 [Member] | Itochu Corporation [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     30.00%  
Solaben 2 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     20 years  
Solaben 3 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     19 years  
Solacor 1 & 2 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership [9]     87.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     2x50 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     1Q 2012 & 1Q 2012  
Contract years left [4]     19 years  
Solacor 1 & 2 [Member] | JGC [Member]        
Nature of the business [Abstract]        
Ownership 13.00%     13.00%
Percentage of non-controlling interests     13.00%  
Helioenergy 1 & 2 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     2x50 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     3Q 2011 & 4Q 2011  
Contract years left [4]     19 years  
Helios 1 & 2 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     2x50 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     3Q 2012 & 3Q 2012  
Contract years left [4]     20 years  
Solnova 1, 3 & 4 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     3x50 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     2Q 2010 & 2Q 2010 & 3Q 2010  
Solnova 1 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     17 years  
Solnova 3 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     17 years  
Solnova 4 [Member]        
Nature of the business [Abstract]        
Contract years left [4]     18 years  
Solaben 1 & 6 [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership     100.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     2x50 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     3Q 2013  
Contract years left [4]     21 years  
Kaxu [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership [10]     51.00%  
Location     South Africa  
Currency [1]     Rand  
Capacity (gross)     100 MW  
Counterparty credit ratings [2],[11]     BB/Baa3/BB+  
COD [3]     1Q 2015  
Contract years left [4]     17 years  
Kaxu [Member] | IDC [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     29.00%  
Kaxu [Member] | Kaxu Community Trust [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     20.00%  
Palmatir [Member]        
Nature of the business [Abstract]        
Type     Renewable (Wind)  
Ownership     100.00%  
Location     Uruguay  
Currency [1]     USD  
Capacity (gross)     50 MW  
Counterparty credit ratings [2],[12]     BBB/Baa2/BBB-  
COD [3]     2Q 2014  
Contract years left [4]     16 years  
Cadonal [Member]        
Nature of the business [Abstract]        
Type     Renewable (Wind)  
Ownership     100.00%  
Location     Uruguay  
Currency [1]     USD  
Capacity (gross)     50 MW  
Counterparty credit ratings [2],[12]     BBB/Baa2/BBB-  
COD [3]     4Q 2014  
Contract years left [4]     17 years  
Seville PV [Member]        
Nature of the business [Abstract]        
Type     Renewable (Solar)  
Ownership [13]     80.00%  
Location     Spain  
Currency [1]     Euro  
Capacity (gross)     1 MW  
Counterparty credit ratings [2]     BBB+/Baa2/A-  
COD [3]     3Q 2006  
Contract years left [4]     18 years  
Seville PV [Member] | Idae [Member]        
Nature of the business [Abstract]        
Percentage of non-controlling interests     20.00%  
[1] Certain contracts denominated in U.S. dollars are payable in local currency.
[2] Reflects the counterparty's credit ratings issued by Standard & Poor's Ratings Services, or S&P, Moody's Investors Service Inc., or Moody's, and Fitch Ratings Ltd, or Fitch.
[3] Commercial Operation Date ("COD").
[4] As of December 31, 2017.
[5] Algerian Energy Company, SPA owns 49% of Skikda and Valoriza Agua, S.L. owns the remaining 16.83%.
[6] Algerian Energy Company, SPA owns 49% of Honaine and Valoriza Agua, S.L. owns the remaining 25.5%.
[7] On September 30, 2013, Liberty Interactive Corporation invested $300,000 thousand in Class A membership interests in exchange for a share of the dividends and taxable loss generated by Solana. As a result of the agreement, Liberty Interactive Corporation will receive between 54.06% and 61.20% of both dividends and taxable loss generated during a period of approximately five years; such percentage will decrease to 22.60% thereafter.
[8] Itochu Corporation, a Japanese trading company, holds 30% of the shares in each of Solaben 2 and Solaben 3.
[9] JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.
[10] Kaxu is owned by the Company (51%), Industrial Development Corporation of South Africa (29%) and Kaxu Community Trust (20%).
[11] Refers to the credit rating of the Republic of South Africa. The offtaker is Eskom, which is a state-owned utility company in South Africa.
[12] Refers to the credit rating of Uruguay, as UTE (Administracion Nacional de Usinas y Transmisoras Electricas) is unrated.
[13] Instituto para la Diversificacion y Ahorro de la Energia ("Idae"), a Spanish state owned company, holds 20% of the shares in Seville PV.