Revenue Recognition - Disaggregated Net Sales (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) unit	Jun. 30, 2020 USD ($) unit	Jun. 30, 2021 USD ($) unit	Jun. 30, 2020 USD ($) unit
Disaggregation of Revenue [Line Items]
Net Sales	$ 143,876	$ 125,596	$ 259,664	$ 263,079
Total Units | unit	7,903,000	6,344,000	13,504,000	12,950,000
Rooftop units
Disaggregation of Revenue [Line Items]
Net Sales	$ 107,370	$ 99,145	$ 194,795	$ 209,975
Total Units | unit	4,657,000	3,746,000	7,616,000	7,807,000
Condensing units
Disaggregation of Revenue [Line Items]
Net Sales	$ 7,302	$ 4,505	$ 13,833	$ 9,003
Total Units | unit	618,000	446,000	1,136,000	854,000
Air handlers
Disaggregation of Revenue [Line Items]
Net Sales	$ 7,265	$ 6,016	$ 13,679	$ 12,263
Total Units | unit	707,000	501,000	1,200,000	1,011,000
Outdoor mechanical rooms
Disaggregation of Revenue [Line Items]
Net Sales	$ 764	$ 434	$ 975	$ 1,349
Total Units | unit	13,000	6,000	20,000	16,000
Water source heat pumps
Disaggregation of Revenue [Line Items]
Net Sales	$ 6,425	$ 3,796	$ 11,090	$ 7,499
Total Units | unit	1,908,000	1,645,000	3,532,000	3,262,000
Part sales
Disaggregation of Revenue [Line Items]
Net Sales	$ 10,717	$ 7,565	$ 18,223	$ 14,078
Other
Disaggregation of Revenue [Line Items]
Net Sales	$ 4,033	$ 4,135	$ 7,069	$ 8,912