Revenue Recognition - Revenue by Source (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 730,153	$ 724,788	$ 575,123
Total revenue	794,247	785,177	632,648
Product
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	518,633	557,336	400,638
Total revenue	518,633	557,336	400,638
Installation
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	101,887	60,826	68,195
Total revenue	101,887	60,826	68,195
Service
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	109,633	95,786	83,267
Total revenue	109,633	95,786	83,267
Electricity
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	0	10,840	23,023
Electricity revenue	64,094	60,389	57,525
Total revenue	$ 64,094	$ 71,229	$ 80,548