Stock Options And Employee Stock Purchase Plan (Narrative) (Details) (USD $)	3 Months Ended					3 Months Ended			3 Months Ended				3 Months Ended		3 Months Ended				12 Months Ended	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Mar. 31, 2013 Stock Options [Member]	Dec. 31, 2012 Stock Options [Member]	Mar. 31, 2013 Restricted Stock And Restricted Stock Unit (RSU) [Member]	Mar. 31, 2012 Restricted Stock And Restricted Stock Unit (RSU) [Member]	Dec. 31, 2012 Restricted Stock And Restricted Stock Unit (RSU) [Member]	Mar. 31, 2013 Employee Stock Purchase Plan [Member]	Mar. 31, 2012 Employee Stock Purchase Plan [Member]	Mar. 31, 2013 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]	Mar. 31, 2013 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]	Mar. 31, 2013 1997 Stock Option Plan [Member]	Mar. 31, 2013 1997 Stock Option Plan [Member] Stock Options [Member]	Mar. 31, 2013 1997 Stock Option Plan [Member] Restricted Stock [Member]	Mar. 31, 2013 2007 Stock Plan [Member]	Dec. 31, 2012 Ziff Davis, Inc. 2012 Equity Incentive Plan [Member]	Mar. 31, 2013 Minimum [Member]
Shares, Granted											0		0						13,035,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period																			5 years
Weighted-Average Grant-Date Fair Value, Granted											$ 0.00
Allocated Share-based Compensation Expense	$ 2,348,000	$ 2,293,000				$ 1,600,000	$ 1,000,000
Weighted-average grant date fair value of options granted	$ 0.00	$ 9.11
Additional shares authorized for issuance															840,000
Number of options outstanding	1,657,861		1,765,461													744,981		912,880
Number of options granted	0
Number of stocks outstanding											663,150	828,475	111,416	115,466			0	111,416
Market value of common stock on the date of grant for incentive stock options									95.00%											85.00%
Maximum issuance of common stock															12,000,000			4,500,000	15,000,000
Maximum earnings withheld by the employees									15.00%
Number of shares purchased under the plan									1,860	1,115
Cash received upon the issuance of common stock	56,000	29,000							56,000	29,000
Number of shares available for issuance									1,643,741
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	1,400,000	1,100,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized				$ 4,100,000	$ 5,000,000	$ 14,100,000		$ 16,000,000