ACQUISITIONS AND DISPOSALS (Summary of Purchase Price and Net Assets Acquired) (Details) - USD ($) $ in Thousands	Apr. 03, 2017	Feb. 28, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash:
Held in escrow account			$ 28,750	$ 28,750
Fair value of net assets acquired:
Goodwill			$ 105,620	$ 107,954	$ 170,667
Nowait, Inc
Cash:
Cash consideration		$ 31,892
Held in escrow account		7,945
Total purchase price		39,837
Fair value of net assets acquired:
Cash and cash equivalents		1,004
Intangible assets		12,670
Goodwill		25,959
Other assets		1,065
Total assets acquired		40,698
Other liabilities		(861)
Total liabilities assumed		(861)
Net assets acquired		$ 39,837
Turnstyle Analytics Inc
Cash:
Cash consideration	$ 16,648
Held in escrow account	3,093
Total purchase price	19,741
Fair value of net assets acquired:
Cash and cash equivalents	30
Intangible assets	4,252
Goodwill	16,048
Other assets	250
Total assets acquired	20,580
Deferred tax liability	(450)
Other liabilities	(389)
Total liabilities assumed	(839)
Net assets acquired	$ 19,741