RESTRUCTURING CHARGES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($) facility	Dec. 31, 2012 USD ($)	Dec. 31, 2011 vacant_facility
Restructuring Cost and Reserve [Line Items]
Number of vacant facilities | vacant_facility					2
Restructuring charges	$ 0	$ 412	$ 3,662
Payments	(328)	(1,097)	$ (6,127)
Restructuring and other charges	2,500
Number of vacated leased facilities | facility			2
Accrued professional fees and deal-related costs	2,500
Accrued restructuring charges	8	366	$ 1,103	$ 3,605
Employee severance costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	506	2,413
Payments	(123)	(358)	(4,406)
Severance expense			600
Accrued restructuring charges	0	128	0	2,005
Employee severance and other costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			2,800
Payments			(4,800)
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	(94)	825
Payments	(205)	(739)	(1,322)
Accrued restructuring charges	$ 8	$ 238	$ 1,103	$ 1,600