BUSINESS COMBINATIONS - Additional Information (Details) $ in Thousands		3 Months Ended										8 Months Ended		12 Months Ended
	Apr. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	[1]	Jun. 30, 2018 USD ($)	[1]	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Professional Fees														$ 700		$ 1,600
Contingent consideration liability incurred in connection with acquisition of business														1,589	$ 0	0
Net income (loss) attributable to parent		$ 46,228	$ 44,615		$ (95,034)		$ (6,888)	$ 47,721	$ 59	$ (9,326)	$ (24,414)			$ (11,079)	$ 14,040	$ (194,587)
Number of Businesses Acquired														1		3
LivingSocial, Inc. [Member]
Business Acquisition [Line Items]
Revenues																$ 3,070,431
Total acquisition price																0
Revenue included in current period statement of operations													$ 4,000
Net loss included in current period statement of operations													$ (9,000)
Business Acquisition, Pro Forma Income (Loss) from Continuing Operations, Net of Tax																$ (182,781)
Cloud Savings [Member]
Business Acquisition [Line Items]
Percentage of outstanding shares acquired	80.00%
Financing obligation incurred in connection with acquisition of business	$ 8,600
Contingent consideration liability incurred in connection with acquisition of business	1,600											$ 1,589
Total acquisition price	$ 74,556													$ 74,556
Net income (loss) attributable to parent														$ 1,100
Other acquisitions [Member]
Business Acquisition [Line Items]
Number of Businesses Acquired																2
Merchant relationships | LivingSocial, Inc. [Member]
Business Acquisition [Line Items]
Intangible assets, useful life																3 years
Merchant relationships | Cloud Savings [Member]
Business Acquisition [Line Items]
Intangible assets, useful life														6 years
Trade names | LivingSocial, Inc. [Member]
Business Acquisition [Line Items]
Intangible assets, useful life																4 years
Trade names | Cloud Savings [Member]
Business Acquisition [Line Items]
Intangible assets, useful life														8 years
Developed technology | LivingSocial, Inc. [Member]
Business Acquisition [Line Items]
Intangible assets, useful life																1 year
Developed technology | Cloud Savings [Member]
Business Acquisition [Line Items]
Intangible assets, useful life														2 years
Other Intangible Assets | Cloud Savings [Member]
Business Acquisition [Line Items]
Intangible assets, useful life														1 year

[1] Income (loss) from continuing operations includes a $40.4 million benefit and $75.0 million charge for the three months ended September 30, 2018 and June 30, 2018, related to our patent litigation with IBM. See Note10, Commitments and Contingencies, for additional information.