XML 37 R1.htm IDEA: XBRL DOCUMENT v3.3.0.814
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2015
Nov. 02, 2015
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2015  
Document Fiscal Year Focus 2015  
Document Fiscal Period Focus Q3  
Trading Symbol WSO  
Entity Registrant Name WATSCO INC  
Entity Central Index Key 0000105016  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   30,249,084
Class B Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   5,034,991