Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share Reconciliation [Abstract]
Net income attributable to j2 Global, Inc. common shareholders	$ 38,916	$ 35,049	$ 60,794	$ 63,814
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	637	701	1,006	1,418
Net earnings available to common shareholders	$ 38,279	$ 34,348	$ 59,788	$ 62,396
Weighted-average outstanding shares of common stock - basic	47,537,597	46,745,596	47,480,315	46,556,428
Dilutive effect of equity incentive plans	315,977	322,171	256,691	355,146
Weighted-average outstanding shares of common stock - diluted	47,853,574	47,067,767	47,737,006	46,911,574
Basic	$ 0.81	$ 0.73	$ 1.26	$ 1.34
Diluted	$ 0.80	$ 0.73	$ 1.25	$ 1.33
Share options excluded from the computation of diluted earnings per share	0		62,000	0