v3.10.0.1
Nature of the business, Concessional assets owned (Details) - USD ($)
$ in Thousands
 6 Months Ended
Sep. 30, 2013
Jun. 30, 2018
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+/Baa3/BBB+
COD   2Q 2013
Contract years left [3]   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   1Q 2011
Contract years left [3]   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   1Q 2014
Contract years left [3]   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   2Q 2015
Contract years left [3]   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   2Q 2014
Contract years left [3]   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   1Q 2014
Contract years left [3]   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+/Baa1/BBB+
COD   4Q 2007
Contract years left [3]   20 years
Skikda [Member]    
Nature of the business [Abstract]    
Type   Water
Ownership [4]   34.20%
Location   Algeria
Currency [1]   USD
Capacity (gross)   3.5 M ft3/day
Counterparty credit ratings [2]   Not rated
COD   1Q 2009
Contract years left [3]   16 years
Skikda [Member] | Algerian Energy Company, SPA [Member]    
Nature of the business [Abstract]    
Percentage of non-controlling interests   49.00%
Skikda [Member] | Sadyt [Member]    
Nature of the business [Abstract]    
Percentage of non-controlling interests   16.83%
Honaine [Member]    
Nature of the business [Abstract]    
Type   Water
Ownership [5]   25.50%
Location   Algeria
Currency [1]   USD
Capacity (gross)   7 M ft3/day
Counterparty credit ratings [2]   Not rated
COD   3Q 2012
Contract years left [3]   20 years
Honaine [Member] | Algerian Energy Company, SPA [Member]    
Nature of the business [Abstract]    
Percentage of non-controlling interests   49.00%
Honaine [Member] | Sadyt [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]   A-/Baa1/A-
COD   1Q 2007 & 2Q 2009
PS10 [Member]    
Nature of the business [Abstract]    
Contract years left [3]   14 years
PS20 [Member]    
Nature of the business [Abstract]    
Contract years left [3]   16 years
Solana [Member]    
Nature of the business [Abstract]    
Type   Renewable (Solar)
Ownership   100.00%
Ownership interest type [6]   Class B
Location   Arizona (USA)
Currency [1]   USD
Capacity (gross)   280 MW
Counterparty credit ratings [2]   A-/A2/A-
COD   4Q 2013
Contract years left [3]   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]   BBB/A3/BBB+
COD   4Q 2014
Contract years left [3]   22 years
Solaben 2 & 3 [Member]    
Nature of the business [Abstract]    
Type   Renewable (Solar)
Ownership [7]   70.00%
Location   Spain
Currency [1]   Euro
Capacity (gross)   2x50 MW
Counterparty credit ratings [2]   A-/Baa1/A-
COD   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 [3]   20 years
Solaben 3 [Member]    
Nature of the business [Abstract]    
Contract years left [3]   19 years
Solacor 1 & 2 [Member]    
Nature of the business [Abstract]    
Type   Renewable (Solar)
Ownership [8]   87.00%
Location   Spain
Currency [1]   Euro
Capacity (gross)   2x50 MW
Counterparty credit ratings [2]   A-/Baa1/A-
COD   1Q 2012 & 1Q 2012
Contract years left [3]   19 years
Solacor 1 & 2 [Member] | JGC [Member]    
Nature of the business [Abstract]    
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]   A-/Baa1/A-
COD   3Q 2011 & 4Q 2011
Contract years left [3]   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]   A-/Baa1/A-
COD   3Q 2012 & 3Q 2012
Contract years left [3]   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]   A-/Baa1/A-
COD   2Q 2010 & 2Q 2010 & 3Q 2010
Solnova 1 [Member]    
Nature of the business [Abstract]    
Contract years left [3]   17 years
Solnova 3 [Member]    
Nature of the business [Abstract]    
Contract years left [3]   17 years
Solnova 4 [Member]    
Nature of the business [Abstract]    
Contract years left [3]   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]   A-/Baa1/A-
COD   3Q 2013
Contract years left [3]   21 years
Seville PV [Member]    
Nature of the business [Abstract]    
Type   Renewable (Solar)
Ownership [9]   80.00%
Location   Spain
Currency [1]   Euro
Capacity (gross)   1 MW
Counterparty credit ratings [2]   A-/Baa1/A-
COD   3Q 2006
Contract years left [3]   18 years
Seville PV [Member] | Idae [Member]    
Nature of the business [Abstract]    
Percentage of non-controlling interests   20.00%
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   1Q 2015
Contract years left [3]   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   2Q 2014
Contract years left [3]   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   4Q 2014
Contract years left [3]   17 years
Mini-Hydro [Member]    
Nature of the business [Abstract]    
Type   Renewable (Hydraulic)
Ownership   100.00%
Location   Peru
Currency [1]   USD
Capacity (gross)   4 MW
Counterparty credit ratings [2]   BBB+/A3/BBB+
COD   2Q 2012
Contract years left [3]   15 years
[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] As of December 31, 2017.
[4] Algerian Energy Company, SPA owns 49% of Skikda and Sadyt (Sociedad Anonima Depuracion y Tratamientos) owns the remaining 16.83%.
[5] Algerian Energy Company, SPA owns 49% of Honaine and Sadyt (Sociedad Anonima Depuracion y Tratamientos) owns the remaining 25.5%.
[6] On September 30, 2013, Liberty Interactive Corporation invested $300,000 thousand in Class A membership interests in exchange for the right to receive between 54.06% and 61.20% of taxable losses and distributions until such time as Liberty reaches a certain rate of return, or the "Flip Date", and 22.60% of taxable losses and distributions thereafter once certain conditions are met.
[7] Itochu Corporation, a Japanese trading company, holds 30% of the shares in each of Solaben 2 and Solaben 3.
[8] JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.
[9] Instituto para la Diversificacion y Ahorro de la Energia ("Idae"), a Spanish state owned company, holds 20% of the shares in Seville PV.
[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.