PROPERTY AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
Dec. 31, 2018 |
|
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment, gross | $ 300,384 | $ 300,384 | $ 267,311 | ||
| Less: Accumulated depreciation and amortization | (166,350) | (166,350) | (124,909) | ||
| Property and equipment, net | 134,034 | 134,034 | 142,402 | ||
| Depreciation and amortization expense | 15,300 | $ 11,700 | 45,600 | $ 29,200 | |
| Leasehold improvements | |||||
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment, gross | 108,980 | 108,980 | 107,611 | ||
| Computer equipment | |||||
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment, gross | 91,464 | 91,464 | 80,093 | ||
| Capitalized software | |||||
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment, gross | 76,656 | 76,656 | 58,908 | ||
| Office furniture and equipment | |||||
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment, gross | $ 23,284 | $ 23,284 | $ 20,699 | ||