COMMITMENTS AND CONTINGENCIES - Employee Retirement Plans and Leases (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Aggregate future minimum payments under noncancelable leases | |||
| 2016 | $ 1,730,000 | ||
| 2017 | 1,234,000 | ||
| 2018 | 648,000 | ||
| 2019 | 265,000 | ||
| 2020 | 630,000 | ||
| Thereafter | 161,000 | ||
| Total minimum lease payments | 4,668,000 | ||
| Rental expense for operating leases | $ 2,900,000 | $ 3,600,000 | $ 3,200,000 |
| T P I Advisory Services Americas Inc | |||
| TPI Employee Retirement Plan | |||
| Period of service after which employees are generally eligible to participate in the Plan | 6 months | ||
| Vesting percentage of employees under profit-sharing plan | 100.00% | ||
| Contribution under profit-sharing plan | $ 1,500,000 | $ 1,600,000 | $ 1,600,000 |
| T P I Advisory Services Americas Inc | Effective January 1, 2008 | |||
| TPI Employee Retirement Plan | |||
| Maximum employer contribution per eligible employee (as a percent) | 3.00% | ||
| Maximum employer contribution per eligible employee, amount | $ 7,950 | ||