FINANCING ARRANGEMENTS AND LONG-TERM DEBT - Compass Convertible Notes (Details) $ / shares in Units, $ in Thousands	Jan. 04, 2011 USD ($) $ / shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 01, 2016 USD ($)
FINANCING ARRANGEMENTS AND LONG-TERM DEBT
Amount outstanding		$ 116,749	$ 125,300
Convertible Notes Payable
FINANCING ARRANGEMENTS AND LONG-TERM DEBT
Amount outstanding		211	211
Note payable
FINANCING ARRANGEMENTS AND LONG-TERM DEBT
Amount outstanding		7,038	$ 7,078
C C G H Limited | Convertible Notes Payable
FINANCING ARRANGEMENTS AND LONG-TERM DEBT
Issuance of debt	$ 6,300
Rate of interest (as a percent)	3.875%
Trigger event condition related to number of consecutive trading days on which market price of common stock exceeds $4 per share on the Nasdaq Global Market	60 days
Conversion rate	0.25
Written notice period after trigger event, that company need to serve for prepayment of all or portion of the outstanding principal amount of the Notes	30 days
Amount outstanding		200
Alsbridge | Note payable
FINANCING ARRANGEMENTS AND LONG-TERM DEBT
Rate of interest (as a percent)			2.00%
Unsecured subordinated promissory notes issued		$ 7,000		$ 7,000
Amount outstanding			$ 7,000
Minimum | C C G H Limited | Convertible Notes Payable
FINANCING ARRANGEMENTS AND LONG-TERM DEBT
Trigger Event condition related to minimum market price of common stock on the Nasdaq Global market (in dollars per share) | $ / shares	$ 4