Acquisitions - Additional Information (Details) - Clean Energy Experts, LLC - USD ($) $ in Millions		1 Months Ended			7 Months Ended
	Apr. 01, 2017	Apr. 30, 2016	Oct. 31, 2015	Apr. 30, 2015	Apr. 30, 2016
Business Acquisition [Line Items]
Purchase consideration, payment of cash				$ 25.0
Purchase consideration, common stock (in shares)				1,900,000
Purchase consideration, amount on issuance of shares				$ 19.1
Payments to acquire businesses		$ 5.0	$ 5.0	$ 15.0	$ 10.0
Purchase consideration, shares issued		250,000	250,000	1,400,000	500,000
Achievement of sales targets and continued employment of key employees acquired in acquisition
Business Acquisition [Line Items]
Payments to acquire businesses	$ 8.8
Purchase consideration, shares issued	599,999