v3.8.0.1
Document and Entity Information - USD ($)
3 Months Ended
Mar. 31, 2018
Apr. 30, 2018
Document Information [Line Items]    
Document Type 10-Q  
Document Period End Date Mar. 31, 2018  
Amendment Flag false  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
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 Accelerated Filer  
Entity Well Known Seasoned Issuer Yes  
Entity Public Float $ 1,365,003,115  
Trading Symbol ETM  
Common Class A [Member]    
Document Information [Line Items]    
Entity Common Stock Shares Outstanding   137,224,044
Common Class B [Member]    
Document Information [Line Items]    
Entity Common Stock Shares Outstanding   4,045,199