Stockholders' Equity - Summary of Noncontrolling Interest Balances By Projects (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Noncontrolling interest	$ 1,058,746	$ 1,253,693	$ 1,175,430	$ 891,246
El Arrayan [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	31,713	31,828
Logan's Gap [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	136,894	171,137
Panhandle One [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	139,496	174,518
Panhandle Two [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	184,255	208,397
Post Rock [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	124,465	160,206
Amazon Wind Farm Flower Ridge [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	102,366	133,950
Broadview Project [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	268,268	307,672
Futtsu [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	11,689	0
Meikle [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest	$ 59,600	$ 65,985