STOCK-BASED COMPENSATION - Summary of Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands |
9 Months Ended |
12 Months Ended |
Sep. 30, 2016 |
Dec. 31, 2015 |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |
|
|
|
|
| Outstanding Beginning Balance, Shares |
|
3,682,019
|
|
|
| Granted, Shares |
|
466,566
|
|
|
| Exercised, Shares |
|
(367,328)
|
|
|
| Expired, Shares |
|
(5,771)
|
|
|
| Forfeited, Shares |
|
(33,707)
|
|
|
| Outstanding Ending Balance, Shares |
|
3,741,779
|
[1] |
3,682,019
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] |
|
|
|
|
| Beginning, Weighted-Average Exercise Price (in usd per share) |
|
$ 11.51
|
|
|
| Granted, Weighted-Average Exercise Price (in usd per share) |
|
14.42
|
|
|
| Exercised, Weighted-Average Exercise Price (in usd per share) |
|
6.27
|
|
|
| Expired, Weighted-Average Exercise Price (in usd per share) |
|
5.73
|
|
|
| Forfeited, Weighted-Average Exercise Price (in usd per share) |
|
10.54
|
|
|
| Ending, Weighted-Average Exercise Price (in usd per share) |
|
$ 12.40
|
|
$ 11.51
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] |
|
|
|
|
| Outstanding, Weighted- Average Remaining Contractual Term (years) |
|
6 years 3 months 7 days
|
|
5 years 11 months 23 days
|
| Outstanding, Aggregate Intrinsic Value |
[2] |
$ 31,586
|
|
|
| Outstanding, Aggregate Intrinsic Value |
[2] |
$ 22,150
|
|
$ 31,586
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract] |
|
|
|
|
| Vested or expected to vest, shares |
[1],[3] |
3,461,891
|
|
|
| Vested or expected to vest, Weighted-Average Exercise Price (in usd per share) |
|
$ 12.57
|
|
|
| Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term |
|
6 years 4 months 9 days
|
|
|
| Vested or expected to vest, Aggregate Intrinsic Value |
[2] |
$ 19,995
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested [Abstract] |
|
|
|
|
| Vested, shares |
|
1,743,949
|
|
|
| Vested, Weighted-Average Exercise Price (in usd per share) |
|
$ 11.73
|
|
|
| Vested, Weighted-Average Remaining Contractual Term |
|
5 years 9 months 3 days
|
|
|
| Vested, Aggregate Intrinsic Value |
[2] |
$ 11,205
|
|
|
| Fair value valuation, estimated fair market value of stock (in dollars per share) |
|
$ 17.78
|
|
$ 19.74
|
| Performance Shares |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |
|
|
|
|
| Outstanding Ending Balance, Shares |
|
993,740
|
|
|
|
|