Financial Instruments - Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Dec. 31, 2019		Jun. 30, 2019
Variable Interest Entity [Line Items]
Restricted cash, current	$ 40,393	[1]	$ 30,804	[1]	$ 23,706
Restricted cash, non-current	139,664	[1]	143,761	[1]	$ 39,351
Restricted cash, total	180,057		174,565
Consolidated Entity, Excluding VIEs
Variable Interest Entity [Line Items]
Restricted cash, current	35,073		28,494
Restricted cash, non-current	51		10
PPA Entities
Variable Interest Entity [Line Items]
Restricted cash, current	827		2,244
Restricted cash, non-current	15,123		15,045
PPA Entities | PPA II
Variable Interest Entity [Line Items]
Restricted cash, current	4,200
Restricted cash, non-current	104,500		108,700
PPA Entities | PPA IIIb
Variable Interest Entity [Line Items]
Restricted cash, current	300
Restricted cash, non-current	20,000		20,000
PPA Entities | Power Purchase Agreements Entities [Member]
Variable Interest Entity [Line Items]
Restricted cash, current	5,320		2,310
Restricted cash, non-current	$ 139,613		$ 143,751

[1] We have variable interest entities which represent a portion of the consolidated balances recorded within these financial statement line items in the condensed consolidated balance sheets (see Note 13, Power Purchase Agreement Programs).