v3.10.0.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Feb. 15, 2019
Document Information [Line Items]    
Document Type 10-K  
Document Period End Date Dec. 31, 2018  
Amendment Flag false  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus FY  
Entity Registrant Name Entercom Communications Corp.  
Entity Central Index Key 0001067837  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Well Known Seasoned Issuer Yes  
Entity Public Float $ 806,397,103  
Trading Symbol ETM  
Common Class A [Member]    
Document Information [Line Items]    
Entity Common Stock Shares Outstanding   137,731,485
Common Class B [Member]    
Document Information [Line Items]    
Entity Common Stock Shares Outstanding   4,045,199