Power Plants - Schedule of Power Plants, Net (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Renewable energy facility [Line Items]
Total power plants in service, at cost		$ 1,466,224		$ 1,466,224		$ 1,246,691
Less: accumulated depreciation		(82,881)		(82,881)		(40,600)
Total power plants in service, net		1,383,343		1,383,343		1,206,091
Power plants, net		1,384,266		1,384,266		1,206,604
Land
Renewable energy facility [Line Items]
Total power plants in service, at cost		10,037		10,037		9,749
Wind power plants
Renewable energy facility [Line Items]
Total power plants in service, at cost		772,568		772,568		562,086
Solar power plants
Renewable energy facility [Line Items]
Total power plants in service, at cost		683,619		683,619		674,856
Construction in progress
Renewable energy facility [Line Items]
Power plants, net		923		923		513
Power plants
Renewable energy facility [Line Items]
Depreciation		12,400	$ 5,900	$ 38,300	$ 11,600
Solar Energy Corporation of India (SECI) | India PSA
Renewable energy facility [Line Items]
Solar generation, subsidy receipts, next twelve months, percentage				50.00%
Solar generation, subsidy receipts, year one, percentage				10.00%
Viability Gap Funding subsidies				$ 8,900
Solar Energy Corporation of India (SECI) | India PSA | Other current assets
Renewable energy facility [Line Items]
Solar generation, government subsidies receivable		1,800		1,800		10,700
Solar Energy Corporation of India (SECI) | India PSA | Other assets
Renewable energy facility [Line Items]
Solar generation, government subsidies receivable		$ 7,100		$ 7,100		$ 7,100
Subsequent Event | Solar Energy Corporation of India (SECI) | India PSA
Renewable energy facility [Line Items]
Solar generation, subsidy receipts, year one, percentage	10.00%