Earnings Per Share - Schedule of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Basic Earnings per Share:
Net income attributable to Watsco, Inc. shareholders	$ 110,073	$ 113,298
Basic earnings per share for Common and Class B common stock	$ 2.84	$ 2.91
Diluted Earnings per Share:
Net income attributable to Watsco, Inc. shareholders	$ 110,073	$ 113,298
Diluted earnings per share for Common and Class B common stock	$ 2.83	$ 2.9
Class B Common Stock
Basic Earnings per Share:
Earnings allocated to Watsco, Inc. shareholders - Basic	$ 9,170	$ 7,466
Common Stock
Basic Earnings per Share:
Earnings allocated to Watsco, Inc. shareholders - Basic	93,489	95,521
Common Stock | Class B Common Stock
Basic Earnings per Share:
Net income attributable to Watsco, Inc. shareholders	110,073	113,298
Less: distributed and undistributed earnings allocated to restricted common stock	7,414	10,311
Earnings allocated to Watsco, Inc. shareholders - Basic	$ 102,659	$ 102,987
Weighted-average common shares outstanding - Basic	36,192,597	35,348,977
Basic earnings per share for Common and Class B common stock	$ 2.84	$ 2.91
Diluted Earnings per Share:
Net income attributable to Watsco, Inc. shareholders	$ 110,073	$ 113,298
Less: distributed and undistributed earnings allocated to restricted common stock	7,411	10,297
Earnings allocated to Watsco, Inc. shareholders - Diluted	$ 102,662	$ 103,001
Weighted-average common shares outstanding - Basic	36,192,597	35,348,977
Effect of dilutive stock options	109,231	155,403
Weighted-average common shares outstanding - Diluted	36,301,828	35,504,380
Diluted earnings per share for Common and Class B common stock	$ 2.83	$ 2.9
Anti-dilutive stock options not included above	169,916	143,372