Revenue Recognition (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) unit	Dec. 31, 2017 USD ($) unit	Dec. 31, 2016 USD ($) unit
Disaggregation of Revenue [Line Items]
Net sales	$ 433,947	$ 405,232	$ 383,977
Total Units | unit	25,152,000	23,381,000	20,898,000
Rooftop Units
Disaggregation of Revenue [Line Items]
Net sales	$ 333,105	$ 317,414	$ 309,641
Total Units | unit	15,273,000	16,003,000	16,764,000
Condensing Units
Disaggregation of Revenue [Line Items]
Net sales	$ 18,282	$ 19,276	$ 13,987
Total Units | unit	2,007,000	2,252,000	1,639,000
Air Handlers
Disaggregation of Revenue [Line Items]
Net sales	$ 21,905	$ 22,570	$ 19,792
Total Units | unit	2,500,000	2,577,000	2,114,000
Outdoor Mechanical Rooms
Disaggregation of Revenue [Line Items]
Net sales	$ 2,408	$ 3,238	$ 4,515
Total Units | unit	38,000	64,000	65,000
Water Source Heat Pumps
Disaggregation of Revenue [Line Items]
Net sales	$ 14,660	$ 9,911	$ 5,835
Total Units | unit	5,334,000	2,485,000	316,000
Part Sales
Disaggregation of Revenue [Line Items]
Net sales	$ 26,732	$ 20,756	$ 20,374
Other
Disaggregation of Revenue [Line Items]
Net sales	$ 16,855	$ 12,067	$ 9,833