Segments and Information about Revenues by Geographic Region (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Segment Reporting Information [Line Items]        
Revenues $ 206,057 $ 170,832 $ 576,290 $ 450,837
United States and Canada [Member]        
Segment Reporting Information [Line Items]        
Revenues 147,820 128,667 412,946 340,229
International [Member]        
Segment Reporting Information [Line Items]        
Revenues $ 58,237 $ 42,165 $ 163,344 $ 110,608