COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) yr	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Future minimum lease commitments under non-cancelable leases [Abstract]
2017	$ 15,827
2018	12,678
2019	11,355
2020	7,610
2021	4,525
Thereafter	2,659
Total	54,654
Operating Lease Commitments [Abstract]
Restructuring Reserve	10,111	$ 7,180	$ 2,343	$ 8,501
Rent expense under operating leases, net of operating subleases	14,100	14,000	15,000
Operating Leases, Income Statement, Sublease Revenue	$ 600	600	700
Purchase Commitments [Abstract]
Maximum purchase commitment period (in years) | yr	1
Aggregate total of non-cancelable purchase commitments	$ 19,500
Product warranty accrual [Roll Forward]
Accrual balance at beginning of year	2,234	2,792	3,501
Accruals for product warranties	2,822	3,025	3,985
Cost of warranty claims	(2,538)	(3,583)	(4,694)
Accrual balance at end of period	2,518	$ 2,234	$ 2,792
Operating Leases on Vacated Facilities [Member]
Operating Lease Commitments [Abstract]
Aggregate obligation of vacated facilies	10,100
Restructuring Reserve	$ 3,100
Standby Letters of Credit [Member] | Office Space - Burlington, Massachusetts [Member]
Operating Lease Commitments [Abstract]
Number of five-year renewal options on corporate office space in Burlington, Massachusetts	2
Minimum exposure	$ 1,200
Letters of Credit Outstanding, Amount	1,300
Standby Letters of Credit [Member] | Office Space - Other Facilities [Member]
Operating Lease Commitments [Abstract]
Letters of Credit Outstanding, Amount	1,000
Standby Letters of Credit [Member] | Other Operating Obligations [Member]
Operating Lease Commitments [Abstract]
Letters of Credit Outstanding, Amount	$ 1,100