Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share Reconciliation [Abstract]
Net income attributable to j2 Global, Inc. common shareholders	$ 22,922	$ 28,539
Net earnings available to participating securities	(412)	(436)
Net earnings available to common shareholders	$ 22,510	$ 28,103
Weighted-average outstanding shares of common stock - basic	45,160,140	46,400,441
Dilutive effect of equity incentive plans	508,027	394,162
Weighted-average outstanding shares of common stock - diluted	45,668,167	46,794,603
Basic	$ 0.50	$ 0.61
Diluted	$ 0.49	$ 0.60
Share options excluded from the computation of diluted earnings per share	15,000	430,319