RESTRUCTURING CHARGES - Summary of the Activity Related to the Accrual for Restructuring Charges Detailed by Event (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	$ 19,319	$ 19,725		$ 19,725
(Credits) charges – Employee termination costs, net of change in estimate	4,882	1,147	$ (1,583)	6,029	$ (1,807)
Non-cash - Other	(217)	(181)
Payments – Employee termination costs	(7,851)	(1,274)
Foreign exchange gain	(1,342)	(98)
Balance at end of period	14,791	19,319		14,791
Quarter Two 2010
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	281	281		281
Non-cash - Other	0	0
Payments – Employee termination costs	0	0
Foreign exchange gain	0	0
Balance at end of period	281	281		281
Quarter Two 2012
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	19	19		19
Non-cash - Other	0	0
Payments – Employee termination costs	229	0
Foreign exchange gain	0	0
Balance at end of period	38	19		38
Quarter One 2013
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	3,384	3,988		3,988
Non-cash - Other	0	0
Payments – Employee termination costs	(196)	(524)
Foreign exchange gain	271	(31)
Balance at end of period	3,306	3,384		3,306
Quarter Three 2013
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	9	9		9
Non-cash - Other	0	0
Payments – Employee termination costs	0	0
Foreign exchange gain	0	0
Balance at end of period	0	9		0
Quarter Three 2014
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	634	920		920
Non-cash - Other	(213)	(175)
Payments – Employee termination costs	(1,064)	(540)
Foreign exchange gain	0	(59)
Balance at end of period	1,008	634		1,008
Quarter Four 2014
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	14,493	14,508		14,508
Non-cash - Other	(4)	(6)
Payments – Employee termination costs	(4,287)	(14)
Foreign exchange gain	(1,616)	(1)
Balance at end of period	9,485	14,493		9,485
Quarter One 2015
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	499	0		0
Non-cash - Other	0	0
Payments – Employee termination costs	(2,508)	(196)
Foreign exchange gain	3	(7)
Balance at end of period	0	499		0
Quarter Two 2015
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	0	0		0
Non-cash - Other	0	0
Payments – Employee termination costs	(25)	0
Foreign exchange gain	0	0
Balance at end of period	673	0		$ 673
Employee Severance
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	4,882
Employee Severance | Quarter Two 2010
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	0	0
Employee Severance | Quarter Two 2012
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	(210)	0
Employee Severance | Quarter One 2013
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	(153)	(49)
Employee Severance | Quarter Three 2013
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	(9)	0
Employee Severance | Quarter Three 2014
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	1,651	488
Employee Severance | Quarter Four 2014
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	899	6
Employee Severance | Quarter One 2015
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	2,006	702
Employee Severance | Quarter Two 2015
Restructuring Cost and Reserve [Line Items]
(Credits) charges – Employee termination costs, net of change in estimate	$ 698	$ 0