XML 47 R51.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Summary of Significant Accounting Policies - Significant Estimates Used by Management in Determining Fair Values of Customer Relationships Acquired (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Minimum      
Goodwill And Intangible Assets [Line Items]      
Discount rates 19.00% 20.00% 17.00%
Customer attrition rates 5.00% 20.00% 15.00%
Maximum      
Goodwill And Intangible Assets [Line Items]      
Discount rates 24.00% 27.00% 25.00%
Customer attrition rates 37.00% 33.00% 78.00%