ACQUISITIONS AND DISPOSALS (Narrative) (Details) - USD ($)				3 Months Ended
	Oct. 10, 2017	Apr. 03, 2017	Feb. 28, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017		Dec. 14, 2017
Business Acquisition [Line Items]
Held in escrow account				$ 28,750,000	$ 28,750,000
Net revenue				223,074,000		$ 198,174,000	[1]
Net income (loss)				(2,286,000)		(4,026,000)	[1],[2],[3]
Nowait, Inc
Business Acquisition [Line Items]
Equity interest in acquiree, percentage			20.00%
Total purchase consideration			$ 39,837,000
Held in escrow account			$ 7,945,000
Escrow deposit duration			2 years
Acquisition-related transaction costs				0		100,000
Net revenue				1,200,000		200,000
Net income (loss)						(800,000)
Turnstyle Analytics Inc
Business Acquisition [Line Items]
Total purchase consideration		$ 19,741,000
Held in escrow account		$ 3,093,000
Escrow deposit duration		18 months
Acquisition-related transaction costs				0		0
Net revenue				$ 700,000
Purchase consideration including acquisition compensation cost		$ 20,600,000
Acquisition compensation cost		$ 1,000,000
Eat 24 Inc
Business Acquisition [Line Items]
Escrow deposit duration				18 months
Gain on disposal of business unit				$ 163,700,000	164,800,000
Disposal related costs					300,000
Goodwill related to disposed asset group					$ 110,800,000
Disposed of by Sale | Eat 24 Inc
Business Acquisition [Line Items]
Held in escrow account	$ 28,800,000
Escrow deposit duration	18 months
Purchase price consideration for sale of subsidiary	$ 251,700,000
Additional purchase consideration received								$ 1,000,000
Loss before provision for income taxes						3,800,000
New Revenue Standard Adjustment | Accounting Standards Update 2014-09
Business Acquisition [Line Items]
Net revenue						851,000
Net income (loss)						$ 754,000
New Revenue Standard Adjustment | Accounting Standards Update 2014-09 | Eat 24 Inc
Business Acquisition [Line Items]
Gain on disposal of business unit				$ (1,100,000)

[1] As of January 1, 2018, the Company adopted ASC 606 using the full retrospective method. Accordingly, the Company has recast certain amounts in the prior period presented. See Note 1 below for additional discussion.

[2] As of January 1, 2018, the Company adopted ASC 606 using the full retrospective method. Accordingly, the Company has recast certain amounts in the prior period presented. See Note 1 below for additional discussion.

[3] As of January 1, 2018, the Company adopted ASC 606 using the full retrospective method. Accordingly, the Company has recast certain amounts in the prior period presented. See Note 1 below for additional discussion.Also as of January 1, 2018, the Company adopted Accounting Standards Update No. 2016-18, "Statement of Cash Flows (Subtopic 230): Restricted Cash," and recast the prior period presented. See Note 1 below for additional discussion.