Related Party Transactions - Additional Information (Details) - RECC - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Solar energy systems and products sales revenue	$ 0.1	$ 2.4	$ 0.3	$ 3.8
Accounts receivable	$ 0.0		$ 0.0		$ 0.1