GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Change in carrying amount of goodwill | |||
| Goodwill | $ 101,315 | $ 75,953 | $ 73,450 |
| Acquired goodwill | 25,362 | 2,503 | |
| Balance at the end of the period | 101,315 | $ 75,953 | |
| Goodwill impairment loss | $ 0 | ||