Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share Reconciliation [Abstract]
Net income attributable to j2 Global, Inc. common shareholders	$ 28,759	$ 27,806	$ 92,573	$ 86,768
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	538	416	1,964	1,455
Net earnings available to common shareholders	$ 28,221	$ 27,390	$ 90,609	$ 85,313
Weighted-average outstanding shares of common stock - basic	46,845,477	45,729,171	46,653,836	45,441,265
Dilutive effect of equity incentive plans	318,435	562,460	334,591	625,339
Weighted-average outstanding shares of common stock - diluted	47,163,912	46,291,631	46,988,427	46,066,604
Basic	$ 0.60	$ 0.60	$ 1.94	$ 1.88
Diluted	$ 0.60	$ 0.59	$ 1.93	$ 1.85
Share options excluded from the computation of diluted earnings per share			0