ACQUISITIONS (ASSETS ACQUIRED TABLE) (DETAILS) - USD ($) $ in Thousands	Dec. 31, 2017	Nov. 08, 2017	Apr. 03, 2017	Dec. 31, 2016	Nov. 09, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Total deferred tax assets, net	$ 34,758			$ 71,754
Goodwill	206,694			129,648		$ 114,183
Accrued employee compensation and benefits	$ 83,997			$ 66,133
Motif [Member]
Business Acquisition [Line Items]
Cash		$ 5,997
Accounts receivable.		5,187
Prepaid Expenses		1,248
Other assets		670
Property, plant and equipment.		2,182
Income Taxes Receivable		1,691
Goodwill		39,272
Total assets acquired		93,447
Accounts payable		2,914
Accrued employee compensation and benefits		5,249
Accrued expenses		104
Deferred tax liabilities		11,402
Deferred revenue.		340
Total liabilities assumed		20,009
Total purchase price		73,438
Motif [Member] | Customer Relationships
Business Acquisition [Line Items]
Intangible assets		$ 37,200
Connextions
Business Acquisition [Line Items]
Accounts receivable.			$ 15,959
Prepaid Expenses			241
Other assets			51
Property, plant and equipment.			7,594
Goodwill			35,272
Total assets acquired			94,117
Accounts payable			1
Accrued employee compensation and benefits			346
Accrued expenses			386
Deferred tax liabilities			15,273
Deferred revenue.			399
Total liabilities assumed			16,405
Total purchase price			77,712
Connextions | Customer Relationships
Business Acquisition [Line Items]
Intangible assets			$ 35,000
Atelka [Member]
Business Acquisition [Line Items]
Cash					$ 2,655
Accounts receivable.					18,449
Other assets					615
Property, plant and equipment.					3,161
Total deferred tax assets, net					638
Goodwill					20,275
Total assets acquired					56,293
Accounts payable					1,199
Accrued employee compensation and benefits					2,418
Accrued expenses					2,597
Other					1,678
Total liabilities assumed					7,892
Total purchase price					48,401
Atelka [Member] | Customer Relationships
Business Acquisition [Line Items]
Intangible assets					$ 10,500