Revenue Recognition - Disaggregated Net Sales (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) unit	Mar. 31, 2020 USD ($) unit
Disaggregation of Revenue [Line Items]
Net Sales	$ 115,788	$ 137,483
Rooftop units
Disaggregation of Revenue [Line Items]
Net Sales	$ 87,425	$ 110,830
Total Units | unit	2,959,000	4,061,000
Condensing units
Disaggregation of Revenue [Line Items]
Net Sales	$ 6,531	$ 4,498
Total Units | unit	518,000	408,000
Air handlers
Disaggregation of Revenue [Line Items]
Net Sales	$ 6,414	$ 6,247
Total Units | unit	493,000	510,000
Outdoor mechanical rooms
Disaggregation of Revenue [Line Items]
Net Sales	$ 211	$ 915
Total Units | unit	7,000	10,000
Water source heat pumps
Disaggregation of Revenue [Line Items]
Net Sales	$ 4,665	$ 3,703
Total Units | unit	1,624,000	1,617,000
Part sales
Disaggregation of Revenue [Line Items]
Net Sales	$ 7,506	$ 6,513
Other
Disaggregation of Revenue [Line Items]
Net Sales	$ 3,036	$ 4,777
Total Units | unit	5,601,000	6,606,000