v3.19.3
SEGMENT AND GEOGRAPHICAL INFORMATION - Long-lived Assets by Geographic Area (Details) - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]    
Long-lived assets $ 581,471 $ 481,209
United States    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Long-lived assets 570,273 471,970
International    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Long-lived assets $ 11,198 $ 9,239