ACQUISITIONS ASSETS ACQUIRED (TABLES) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Nov. 04, 2020	Aug. 05, 2020	Feb. 07, 2020
Business Acquisition [Line Items]
Operating lease assets	$ 112,129	$ 120,820
Goodwill	362,862	363,502
Operating lease liability - short-term	43,043	43,651
Accrued employee compensation and benefits	161,792	163,658
Operating lease liability - long-term	$ 89,967	$ 98,277
Voice Foundry US
Business Acquisition [Line Items]
Accounts receivable.				$ 3,758
Prepaid Expenses				345
Goodwill				35,881
Total assets acquired				47,084
Accounts payable				289
Accrued employee compensation and benefits				741
Deferred revenue.				170
Total liabilities assumed				1,200
Total purchase price				45,884
Voice Foundry US | Trade Names [Member]
Business Acquisition [Line Items]
Intangible assets				400
Voice Foundry US | Noncompete Agreements [Member]
Business Acquisition [Line Items]
Intangible assets				150
Voice Foundry US | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets				$ 6,550
Voice Foundry ASEAN
Business Acquisition [Line Items]
Cash			$ 1,300
Accounts receivable.			937
Prepaid Expenses			115
Property, plant and equipment.			274
Income Taxes Receivable			30
Goodwill			14,418
Total assets acquired			20,474
Accounts payable			960
Accrued employee compensation and benefits			113
Deferred tax liabilities			1,013
Deferred revenue.			236
Other accrued assets liabilities, net			(78)
Total liabilities assumed			2,244
Total purchase price			18,230
Voice Foundry ASEAN | Trade Names [Member]
Business Acquisition [Line Items]
Intangible assets			300
Voice Foundry ASEAN | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets			$ 3,100
Serendebyte
Business Acquisition [Line Items]
Cash					$ 3,123
Accounts receivable.					1,243
Prepaid Expenses					1,327
Property, plant and equipment.					20
Deferred tax assets.					14
Goodwill					9,033
Total assets acquired					17,080
Accounts payable					120
Accrued employee compensation and benefits					1,025
Accrued income taxes					170
Accrued expenses					2,208
Deferred tax liabilities					629
Total liabilities assumed					4,152
Total purchase price					12,928
Serendebyte | Trade Names [Member]
Business Acquisition [Line Items]
Intangible assets					400
Serendebyte | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets					$ 1,920