Business Acquisition Business Acquisitions (Allocation Of Aggregate Purchase Price) (Details) (USD $)	Dec. 31, 2010	Dec. 31, 2010 Developed Technology Rights [Member]	Dec. 31, 2010 Trade Names [Member]	Dec. 31, 2010 Customer Relationships [Member]	Dec. 31, 2010 Noncompete Agreements [Member]	Dec. 31, 2012 Ziff Davis, Inc [Member]	Dec. 31, 2012 Ziff Davis, Inc [Member] Developed Technology Rights [Member]	Dec. 31, 2012 Ziff Davis, Inc [Member] Trade Names [Member]	Dec. 31, 2012 Ziff Davis, Inc [Member] Customer Relationships [Member]	Dec. 31, 2012 Ziff Davis, Inc [Member] Advertiser Relationship [Member]	Dec. 31, 2012 Ziff Davis, Inc [Member] Licensing Relationship [Member]	Dec. 31, 2010 Protus Ip Solutions Inc [Member]	Dec. 31, 2010 Protus Ip Solutions Inc [Member] Developed Technology Rights [Member]	Dec. 31, 2010 Protus Ip Solutions Inc [Member] Trade Names [Member]	Dec. 31, 2010 Protus Ip Solutions Inc [Member] Customer Relationships [Member]	Dec. 31, 2010 Protus Ip Solutions Inc [Member] Noncompete Agreements [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	$ 4,262,000					$ 842,000	$ 4,780,000					$ 3,137,000
Business Acquisition Purchase Price Allocation Current Noncurrent Assets Prepaid Expense and Other Assets	2,122,000					1,283,000						1,812,000
Business Acquisition, Purchase Price Allocation, Deferred Taxes Asset (Liability), Net, Noncurrent	(12,408,000)					1,139,000						(13,796,000)
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets		2,600,000	27,741,000	35,832,000	2,588,000	2,540,000		37,730,000	5,380,000	14,500,000	4,910,000		2,600,000	26,982,000	29,640,000	1,576,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	195,633,000					112,882,000						164,498,000
Business Acquisition, Purchase Price Allocation, Current Liabilities, Deferred Revenue	(6,683,000)											(4,928,000)
Business Acquisition, Purchase Price Allocation, Liabilities Assumed	29,200,000					28,800,000						25,600,000
Total consideration of transaction, net of cash acquired						200,436,000						233,000,000
Business Acquisition, Purchase Price Allocation, Noncontrolling Interest						8,600,000
Business Acquisition, Purchase Price Allocation, Goodwill, Expected Tax Deductible Amount	15,800,000					12,900,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	277,100,000
Business Acquisition, Purchase Price Allocation, Current Assets, Receivables	3,969,000					14,450,000						2,338,000
Business Acquisition, Purchase Price Allocation, Current Liabilities, Accounts Payable												(1,219,000)
Business Acquisition, Purchase Price Allocation, Current Liabilities, Accrued Liabilities												(5,295,000)
Business Acquisition, Cost of Acquired Entity, Cash Paid	247,913,000					163,100,000						207,345,000
Business Acquisition Purchase Price Allocation Current Liabilities Accounts Payable And Other	$ (7,743,000)