v2.4.0.6
Document and Entity Information (USD $)
12 Months Ended
Dec. 31, 2012
Jun. 29, 2012
Feb. 25, 2013
Common Stock
Feb. 25, 2013
Class B Common Stock
Document Information [Line Items]        
Document Type 10-K      
Amendment Flag false      
Document Period End Date Dec. 31, 2012      
Document Fiscal Year Focus 2012      
Document Fiscal Period Focus FY      
Trading Symbol WSO      
Entity Registrant Name WATSCO INC      
Entity Central Index Key 0000105016      
Current Fiscal Year End Date --12-31      
Entity Well-known Seasoned Issuer Yes      
Entity Current Reporting Status Yes      
Entity Voluntary Filers No      
Entity Filer Category Large Accelerated Filer      
Entity Common Stock, Shares Outstanding     29,954,181 4,610,821
Entity Public Float   $ 1,873,000,000