Discontinued Operations - Balance Sheet Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Jan. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	$ 0	$ 79,020		$ 120,861	$ 57,762
Total current assets of discontinued operations	0			179,689
Long-term assets of discontinued operations	0			538,931
Total current liabilities of discontinued operations	0			172,670
Long-term liabilities of discontinued operations	0			7,708
Reduction to retained earnings	(3,790,452)			(4,010,737)
Transfer of Cash	28,523	$ 0
Accumulated other comprehensive loss associated with foreign currency translation adjustments reclassified to retained earnings	13,400
GoTo Business Division [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash				120,861
Accounts receivable, net				44,734
Prepaid expenses and other current assets				14,094
Total current assets of discontinued operations				179,689
Property and equipment, net				81,866
Goodwill				380,917
Other intangible assets, net				54,312
Deferred tax assets, net				18,496
Other assets				3,340
Long-term assets of discontinued operations				538,931
Total major classes of assets of discontinued operations				718,620
Accounts payable				11,333
Accrued expenses and other current liabilities				46,088
Current portion of deferred revenues				115,249
Total current liabilities of discontinued operations				172,670
Long-term portion of deferred revenues				4,224
Other liabilities				3,484
Long-term liabilities of discontinued operations				7,708
Total major classes of liabilities of discontinued operations				$ 180,378
Reduction to retained earnings			$ 478,200
Reduction to net assets			$ 464,800
Accumulated Foreign Currency Adjustment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated other comprehensive loss associated with foreign currency translation adjustments reclassified to retained earnings	13,400
Accumulated Foreign Currency Adjustment [Member] | GoTo Business Division [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated other comprehensive loss associated with foreign currency translation adjustments reclassified to retained earnings	$ 13,400