Revenue Recognition - Revenue by Source (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers													$ 724,788
Total revenue from contract with customers														$ 575,123
Total revenue	$ 213,543	$ 224,307	$ 200,326	$ 147,001	$ 157,145	$ 168,619	$ 138,302	$ 168,582	$ 347,327	$ 306,884	$ 571,634	$ 475,503	785,177	632,648	$ 365,623
Product
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers													557,336
Total revenue from contract with customers														400,638
Total revenue	158,427	163,902	144,081	90,926	103,937	102,433	78,497	115,771	235,007	194,268	398,909	296,701	557,336	400,638	157,192
Installation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers													60,826
Total revenue from contract with customers														68,195
Total revenue	14,429	21,102	13,076	12,219	11,066	24,691	19,643	12,795	25,295	32,438	46,397	57,129	60,826	68,195	57,937
Service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers													95,786
Total revenue from contract with customers														83,267
Total revenue	25,628	23,665	23,026	23,467	21,778	21,056	20,299	20,134	46,493	40,433	70,158	61,489	95,786	83,267	74,892
Electricity
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers													10,840
Total revenue from contract with customers														23,023
Operating lease revenue													60,389	57,525
Total revenue	$ 15,059	$ 15,638	$ 20,143	$ 20,389	$ 20,364	$ 20,439	$ 19,863	$ 19,882	$ 40,532	$ 39,745	$ 56,170	$ 60,184	$ 71,229	$ 80,548	$ 75,602