Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Jul. 14, 2016	May 16, 2016	Jan. 06, 2016	Aug. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 295,137	$ 237,113
Gross Profit	146,388	100,637
Net income (loss)	(31,578)	14,081
Interest expense, net	39,398	30,237
Income tax expense (benefit)	5,774	(99,902)
Depreciation	13,111	13,172
Amortization of other intangible assets	34,267	29,874
Stock-based compensation	12,924	18,388
Restructuring expenses	5,627	11,602
Transaction expenses and charges	580	31,120
Gain of unconsolidated entities	0	(10,727)
Impairment of other long lived assets	0	1,437
Adjusted EBITDA	80,103	39,282
Total assets	2,739,267	2,756,274	$ 2,756,274
Other income		11,400
Loss of unconsolidated entities	0	683
Web Presence Unit
Segment Reporting Information [Line Items]
Revenue	197,348	198,048
Gross Profit	86,616	89,885
Net income (loss)	(23,626)	40,134
Interest expense, net	16,879	17,016
Income tax expense (benefit)	10,551	(84,258)
Depreciation	9,238	8,977
Amortization of other intangible assets	15,905	19,755
Stock-based compensation	11,100	14,647
Restructuring expenses	2,335	171
Transaction expenses and charges	0	30,357
Gain of unconsolidated entities	0	(10,727)
Impairment of other long lived assets	0	1,437
Adjusted EBITDA	42,382	37,509
Total assets	1,476,006	1,523,170
Email Marketing Unit
Segment Reporting Information [Line Items]
Revenue	97,789	39,065
Gross Profit	59,772	10,752
Net income (loss)	(7,952)	(26,053)
Interest expense, net	22,519	13,221
Income tax expense (benefit)	(4,777)	(15,644)
Depreciation	3,873	4,195
Amortization of other intangible assets	18,362	10,119
Stock-based compensation	1,824	3,741
Restructuring expenses	3,292	11,431
Transaction expenses and charges	580	763
Gain of unconsolidated entities	0	0
Impairment of other long lived assets	0	0
Adjusted EBITDA	37,721	1,773
Total assets	$ 1,263,261	$ 1,233,104
WZ (UK) Ltd.
Segment Reporting Information [Line Items]
Ownership interest				86.40%	77.50%	57.50%	49.00%