XML 96 R1.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2019
Feb. 18, 2020
Jun. 30, 2019
Cover [Abstract]      
Entity Registrant Name CSG SYSTEMS INTERNATIONAL, INC.    
Entity Central Index Key 0001005757    
Document Type 10-K    
Document Period End Date Dec. 31, 2019    
Amendment Flag false    
Entity Small Business false    
Entity Emerging Growth Company false    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Trading Symbol CSGS    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 1,158,870,134
Entity Common Stock, Shares Outstanding   32,852,226  
Entity Current Reporting Status Yes    
Entity Shell Company false    
Entity File Number 0-27512    
Entity Tax Identification Number 47-0783182    
Entity Address, Address Line One 6175 S. Willow Drive    
Entity Address, Address Line Two 10th Floor    
Entity Address, City or Town Greenwood Village    
Entity Address, State or Province CO    
Entity Address, Postal Zip Code 80111    
City Area Code (303)    
Local Phone Number 200-2000    
Entity Incorporation, State or Country Code DE    
Document Annual Report true    
Document Transition Report false    
Title of 12(b) Security Common Stock, Par Value $0.01 Per Share    
Security Exchange Name NASDAQ    
Entity Interactive Data Current Yes    
Documents Incorporated by Reference

Portions of the Registrant’s Definitive Proxy Statement for its 2020 Annual Meeting of Stockholders to be filed on or prior to April 29, 2020, are incorporated by reference into Part III of this Report.