RESTRUCUTRING CHARGES (Cost Incurred and Expected to be Incurred) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 661	$ 3,558	$ 0
Cumulative Costs Incurred to Date	4,219
Employee termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	269	3,300
Cumulative Costs Incurred to Date	3,569
Facility exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	134	0
Cumulative Costs Incurred to Date	134
Other related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	258	258
Cumulative Costs Incurred to Date	516
Operating segment | MMS
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	255
Cumulative Costs Incurred to Date	255
Operating segment | MMS | Employee termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	255
Cumulative Costs Incurred to Date	255
Operating segment | MMS | Facility exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0
Operating segment | MMS | Other related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	0
Operating segment | ATA
Restructuring Cost and Reserve [Line Items]
Restructuring charges	661	3,303
Cumulative Costs Incurred to Date	3,964
Operating segment | ATA | Employee termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	269	3,045
Cumulative Costs Incurred to Date	3,314
Operating segment | ATA | Facility exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	134	0
Cumulative Costs Incurred to Date	134
Operating segment | ATA | Other related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	258	$ 258
Cumulative Costs Incurred to Date	$ 516