Revenue Recognition - Disaggregated Net Sales (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) unit	Jun. 30, 2019 USD ($) unit	Jun. 30, 2020 USD ($) unit	Jun. 30, 2019 USD ($) unit
Disaggregation of Revenue [Line Items]
Net Sales	$ 125,596	$ 119,437	$ 263,079	$ 233,259
Rooftop units
Disaggregation of Revenue [Line Items]
Net Sales	$ 99,145	$ 88,757	$ 209,975	$ 177,100
Total Units | unit	3,746,000	3,797,000	7,807,000	7,559,000
Condensing units
Disaggregation of Revenue [Line Items]
Net Sales	$ 4,505	$ 5,156	$ 9,003	$ 9,206
Total Units | unit	446,000	479,000	854,000	873,000
Air handlers
Disaggregation of Revenue [Line Items]
Net Sales	$ 6,016	$ 6,033	$ 12,263	$ 11,627
Total Units | unit	501,000	537,000	1,011,000	1,117,000
Outdoor mechanical rooms
Disaggregation of Revenue [Line Items]
Net Sales	$ 434	$ 825	$ 1,349	$ 1,307
Total Units | unit	6,000	10,000	16,000	21,000
Water source heat pumps
Disaggregation of Revenue [Line Items]
Net Sales	$ 3,796	$ 6,822	$ 7,499	$ 12,666
Total Units | unit	1,645,000	2,377,000	3,262,000	4,666,000
Part sales
Disaggregation of Revenue [Line Items]
Net Sales	$ 7,565	$ 8,799	$ 14,078	$ 15,289
Other
Disaggregation of Revenue [Line Items]
Net Sales	$ 4,135	$ 3,045	$ 8,912	$ 6,064
Total Units | unit	6,344,000	7,200,000	12,950,000	14,236,000