Segments and Information about Revenues by Geographic Region (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Segment Reporting Information [Line Items]        
Revenues $ 212,880 $ 198,535 $ 412,786 $ 370,233
United States and Canada        
Segment Reporting Information [Line Items]        
Revenues 146,102 141,478 287,598 265,126
International        
Segment Reporting Information [Line Items]        
Revenues $ 66,778 $ 57,057 $ 125,188 $ 105,107