Reportable Business Segments (Segment Data) (Details)	3 Months Ended
	Mar. 31, 2021 USD ($) Segment	Mar. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | Segment	3
Net sales
Net sales	$ 930,500,000	$ 723,800,000
Segment profit (loss)
Total segment profit	115,700,000	37,600,000
Reconciliation to Operating income:
Net Loss(gain) from natural disaster	0	1,600,000
Loss from natural disasters, net of insurance recoveries	0	(1,600,000)
Items in Losses (gains) and other expenses, net that are excluded from segment profit (loss)	1,500,000	(900,000)
Restructuring charges	100,000	500,000
Operating income	114,100,000	36,400,000
Residential Heating & Cooling [Member]
Net sales
Net sales	606,300,000	442,100,000
Segment profit (loss)
Total segment profit	96,400,000	32,500,000
Residential Heating & Cooling [Member] | Sales Channel, Directly to Consumer [Member]
Reconciliation to Operating income:
Revenue from Contract with Customer, Excluding Assessed Tax	0.67	0.73
Commercial Heating & Cooling [Member]
Net sales
Net sales	199,200,000	178,400,000
Segment profit (loss)
Total segment profit	27,400,000	18,700,000
Commercial Heating & Cooling [Member] | Equipment Sales [Member]
Reconciliation to Operating income:
Revenue from Contract with Customer, Excluding Assessed Tax	0.83	0.84
Refrigeration [Member]
Net sales
Net sales	125,000,000.0	103,300,000
Segment profit (loss)
Total segment profit	7,900,000	700,000
Corporate & Other [Member]
Segment profit (loss)
Total segment profit	$ 16,000,000.0	$ 14,300,000