Consolidated Statements Of Stockholders' Equity Statement (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stockholders' equity attributable to j2 Global, Inc.	$ 706,418	$ 594,695	$ 706,418	$ 594,695	$ 554,375	$ 431,745
Stockholders' Equity Attributable to Noncontrolling Interest	0	(100)	0	(100)	0	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	706,418	594,595	706,418	594,595	554,375	431,745
Net earnings attributable to j2 Global, Inc. common shareholders	20,754	30,203	107,522	121,580	114,766
Net Income (Loss) Attributable to Noncontrolling Interest			0	83	0
Comprehensive income attributable to j2 Global, Inc.			111,845	124,969	113,324
Preferred Stock, Accretion of Redemption Discount			0	(183)
Additional paid-in capital	216,872	169,542	216,872	169,542
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			100
Common Stock, Shares, Issued	46,105,076	45,094,191	46,105,076	45,094,191
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(569,204)	(357,234)	(1,820,678)
Common Stock [Member]
Shares, Outstanding	46,105,076	45,094,191	46,105,076	45,094,191	55,389,636	53,700,629
Stockholders' equity attributable to j2 Global, Inc.	461	451	461	451	554	537
Stock Issued During Period, Shares, New Issues			234,025
Stock Issued During Period, Value, New Issues			2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			569,204	357,234	1,820,678
Stock Issued During Period, Value, Stock Options Exercised			6	4	18
Stock Issued During Period, Shares, Employee Stock Purchase Plans			5,402	5,797	5,235
Stock Issued During Period, Value, Employee Stock Purchase Plan			0	0	0
Stock Issued During Period, Shares, Restricted Stock Award, Gross			308,082	204,052	155,024
Stock Issued During Period, Value, Restricted Stock Award, Gross			3	2	1
Common Shares Repurchased And Retired During Period Shares			(29,950)	(10,806,648)	(248,152)
Common Shares Repurchased And Retired During Period Value			0	(108)	(2)
Stock Repurchased and Retired During Period, Shares			(75,878)	(55,880)	(43,778)
Stock Repurchased and Retired During Period, Value			(1)	(1)	0
Series A Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues			5,064
Stock Issued During Period, Value, New Issues			0
Additional paid-in capital	4,774		4,774
Series B Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues			4,155
Stock Issued During Period, Value, New Issues			0
Additional paid-in capital	6,575		6,575
Additional Paid-in Capital [Member]
Stockholders' equity attributable to j2 Global, Inc.	216,872	169,542	216,872	169,542	197,374	164,769
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			22,900
Stock Issued During Period, Value, Stock Options Exercised			13,598	5,642	14,404
Stock Issued During Period, Value, Employee Stock Purchase Plan			213	157	142
Stock Issued During Period, Value, Restricted Stock Award, Gross			(3)	(2)	(1)
Common Shares Repurchased And Retired During Period Value			(684)	(42,580)	(3,616)
Stock Repurchased and Retired During Period, Value			(1,506)	(1,093)	(853)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition			9,585	9,083	8,968
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			3,227	961	13,561
Treasury Stock [Member]
Shares, Outstanding	0	0	0	0	(8,680,568)	(8,680,568)
Stockholders' equity attributable to j2 Global, Inc.	0	0	0	0	(112,671)	(112,671)
Common Shares Repurchased And Retired During Period Shares			0	8,680,568
Common Shares Repurchased And Retired During Period Value			0	112,671
Retained Earnings [Member]
Stockholders' equity attributable to j2 Global, Inc.	484,850	424,790	484,850	424,790	472,595	381,145
Net earnings attributable to j2 Global, Inc. common shareholders			107,522	121,580	114,766
Dividends, Common Stock, Cash			(45,135)	(40,263)	(19,199)
Common Shares Repurchased And Retired During Period Value			(2,395)	(129,171)	(4,142)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition			68	49	25
Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' equity attributable to j2 Global, Inc.	4,235	(88)	4,235	(88)	(3,477)	(2,035)
Comprehensive income attributable to j2 Global, Inc.			$ 4,323	$ 3,389	$ (1,442)