v3.10.0.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Feb. 15, 2019
Jun. 30, 2018
Document Documentand Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Trading Symbol IEX    
Entity Registrant Name IDEX CORP /DE/    
Entity Central Index Key 0000832101    
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   75,792,814  
Entity Public Float     $ 10,446,083,118
Entity Emerging Growth Company false    
Entity Small Business false    
Entity Shell Company false