Discontinued Operations - Income Statement Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income tax	$ 0	$ 20,164	$ (42,704)	$ 44,982
Separation costs	$ 0	900	500	1,700
GoTo Business Division [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues		172,515	58,215	508,413
Cost of net revenues		39,804	15,456	116,216
Gross margin		132,711	42,759	392,197
Research and development		25,146	9,108	70,983
Sales, marketing and services		47,353	20,881	158,702
General and administrative		14,986	7,636	46,572
Amortization of other intangible assets		3,480	1,176	10,618
Restructuring		(115)	3,189	830
Separation		16,663	40,573	44,444
Total operating expenses		107,513	82,563	332,149
Income (loss) from discontinued operations before income taxes		25,198	(39,804)	60,048
Income tax expense		5,034	2,900	15,066
Income (loss) from discontinued operations, net of income tax		$ 20,164	$ (42,704)	$ 44,982