Quarterly report pursuant to Section 13 or 15(d)

Our Portfolio - Equity Method Investments (Details)

v3.19.1
Our Portfolio - Equity Method Investments (Details) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]    
Carrying Value $ 458,916 $ 471,044
2007 Vento I, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value 93,000  
Buckeye Wind Energy Class B Holdings, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value 71,000  
Northern Frontier Wind, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value 65,000  
3D Engie, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value 49,000  
Invenergy Gunsight Mountain Holdings, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value 37,000  
Helix Fund, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value 26,000  
Other Transactions [Member]    
Schedule of Equity Method Investments [Line Items]    
Carrying Value $ 118,000