STOCK BASED AND DEFERRED COMPENSATION - Summary of Additional Information Regarding Stock Plan (Details) - USD ($) $ in Thousands |
9 Months Ended | 12 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2017 |
Dec. 31, 2016 |
|||
Summary of stock based compensation agreements | ||||
Unrecognized stock-based compensation cost | $ 21,920 | $ 18,528 | ||
Weighted average years expense recognition period | 2 years 9 months | 2 years 6 months 22 days | ||
Total stock-based awards outstanding (in shares) | [1] | 1,302,176 | 1,147,271 | |
|