ACQUIRED INTANGIBLE ASSETS - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands |
Sep. 30, 2019 |
Jun. 30, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|---|---|---|---|
| Acquired Finite-Lived Intangible Assets [Line Items] | ||||||
| Cost | $ 115,274 | $ 116,633 | ||||
| Accumulated Amortization | (42,481) | (39,531) | ||||
| Net | 72,793 | $ 84,216 | 77,102 | $ 81,130 | $ 85,514 | $ 14,334 |
| Technology assets | ||||||
| Acquired Finite-Lived Intangible Assets [Line Items] | ||||||
| Cost | 54,630 | 45,978 | ||||
| Accumulated Amortization | (30,682) | (28,420) | ||||
| Net | 23,948 | 17,558 | ||||
| Customer assets | ||||||
| Acquired Finite-Lived Intangible Assets [Line Items] | ||||||
| Cost | 44,045 | 57,109 | ||||
| Accumulated Amortization | (6,089) | (8,068) | ||||
| Net | 37,956 | 49,041 | ||||
| Trade name | ||||||
| Acquired Finite-Lived Intangible Assets [Line Items] | ||||||
| Cost | 11,300 | 11,300 | ||||
| Accumulated Amortization | (3,767) | (1,648) | ||||
| Net | 7,533 | 9,652 | ||||
| Other | ||||||
| Acquired Finite-Lived Intangible Assets [Line Items] | ||||||
| Cost | 5,299 | 2,246 | ||||
| Accumulated Amortization | (1,943) | (1,395) | ||||
| Net | $ 3,356 | $ 851 |