Acquisitions - 2016 and 2015 Acquisition Narrative (Details) $ / shares in Units, $ in Millions								1 Months Ended		3 Months Ended	6 Months Ended
	Apr. 08, 2016 USD ($) MW	Dec. 31, 2015 USD ($) shares	Oct. 07, 2015 USD ($) power_plant MW	Sep. 18, 2015 USD ($) $ / shares MW shares	Aug. 06, 2015 USD ($) MW	Jun. 09, 2015 USD ($) MW	May 14, 2015 USD ($) wind_project MW	Mar. 31, 2016 shares	Jul. 31, 2015 hydro_power_project director	Jun. 30, 2016 USD ($) shares	Jun. 30, 2016 USD ($)	Apr. 30, 2016	Feb. 24, 2016 power_plant MW	Jul. 31, 2015 wind_project	Jul. 31, 2015 MW
Renova Energia S.A.
Business Acquisition [Line Items]
Ownership interest threshold for board of directors appointment rights				28.00%
NPS Star and WXA
Business Acquisition [Line Items]
Percentage of voting interests acquired													49.00%
Number of projects acquired | power_plant													2
Capacity of acquired power plants | MW													35.6
NPS Star
Business Acquisition [Line Items]
Number of projects acquired | power_plant													3
Capacity of acquired power plants | MW													17.8
WXA
Business Acquisition [Line Items]
Number of projects acquired | power_plant													3
Capacity of acquired power plants | MW													17.8
Alto Cielo Preliminary
Business Acquisition [Line Items]
Percentage of voting interests acquired	100.00%
Capacity of acquired power plants | MW	26.4
Payments to acquire businesses	$ 32.3
Escrow deposits related to property sale										$ 1.8	$ 1.8
Certain India project
Business Acquisition [Line Items]
Percentage of voting interests acquired												51.00%
Honiton
Business Acquisition [Line Items]
Percentage of voting interests acquired							100.00%
Number of projects acquired | wind_project							3
Capacity of acquired power plants | MW							148.5
Payments to acquire businesses							$ 109.1
NSM 24
Business Acquisition [Line Items]
Percentage of voting interests acquired						51.00%
Capacity of acquired power plants | MW						24.0
Payments to acquire businesses						$ 9.1
Subsequent equity interest in acquisition, percent						49.00%
Equity interest in acquiree, fair value						$ 8.7
Remeasurement gain						$ 1.4
Witkop / Soutpan
Business Acquisition [Line Items]
Payments to acquire businesses					$ 38.7
Fair value of aggregate interest					$ 47.8
Witkop / Soutpan | SunEdison
Business Acquisition [Line Items]
Percentage of voting interests acquired					41.30%
Capacity of acquired power plants | MW					32.6
Equity interest prior to acquisition					9.70%
Renova (Salvador / Bahia)
Business Acquisition [Line Items]
Number of projects acquired | wind_project														2
Capacity of acquired power plants | MW				306.7
Payments to acquire businesses				$ 117.3						117.7
Acquisition agreement, number of projects to be acquired									1					2
Acquisition agreement, capacity of projects to be acquired (in MW) | MW															336.2
Acquisition purchase price				$ 321.3						$ 320.7
Common stock issued in acquisition (in shares) | shares				20,327,499
put / call arrangement transferred in acquisition				$ 20.4
Amount held in escrow pending lender release letter		$ 49.2
Renova (Salvador / Bahia) | SunEdison
Business Acquisition [Line Items]
put / call arrangement transferred in acquisition				20.4
FERSA Final
Business Acquisition [Line Items]
Number of projects acquired | power_plant			3
Capacity of acquired power plants | MW			101.6
Acquisition purchase price			$ 72.4
Repayments of long-term debt			$ 39.0
Common Stock | Renova (Salvador / Bahia)
Business Acquisition [Line Items]
Common stock issued in acquisition (in shares) | shares		20,327,499								20,223,581
Value assigned to equity acquisition				$ 183.6						$ 182.6	$ 182.6
Shares issued or issuable, value assigned (in usd per share) | $ / shares				$ 9.03
Omnibus agreement | Renova (Salvador / Bahia) | Renova
Business Acquisition [Line Items]
Payments on (proceeds from) previous acquisition				$ 5.0
Omnibus agreement | Renova (Salvador / Bahia) | Renova Energia S.A.
Business Acquisition [Line Items]
Number of board of director appointments | director									1
Counterparty ownership interest threshold, percentage of shares owned											100.00%
Common Class A | Omnibus agreement | Renova (Salvador / Bahia) | Global LLC
Business Acquisition [Line Items]
Common stock terminated in business acquisition (in shares) | shares								19,221,671