Financial Instruments - Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2020		Dec. 31, 2019		Sep. 30, 2019
Variable Interest Entity [Line Items]
Restricted cash, current	$ 47,212	[1]	$ 30,804	[1]	$ 14,486
Restricted cash, non-current	131,916	[1]	143,761	[1]	$ 116,890
Restricted cash, total	179,128		174,565
Consolidated Entity, Excluding VIEs
Variable Interest Entity [Line Items]
Restricted cash, current	33,240		28,494
Restricted cash, non-current	252		10
PPA Entities
Variable Interest Entity [Line Items]
Restricted cash, current	1,095		2,244
Restricted cash, non-current	15,327		15,045
PPA Entities | PPA II
Variable Interest Entity [Line Items]
Restricted cash, current	12,400
Restricted cash, non-current	96,300		108,700
Restricted cash, total	108,700
PPA Entities | PPA IIIb
Variable Interest Entity [Line Items]
Restricted cash, current	500
Restricted cash, non-current	20,000		20,000
PPA Entities | Power Purchase Agreements Entities
Variable Interest Entity [Line Items]
Restricted cash, current	13,972		2,310
Restricted cash, non-current	$ 131,664		$ 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).