Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share Reconciliation [Abstract]
Net income attributable to j2 Global, Inc. common shareholders	$ 29,943	$ 21,877
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	412	360
Net earnings available to common shareholders	$ 29,531	$ 21,517
Weighted-average outstanding shares of common stock - basic	47,966,718	47,422,396
Dilutive effect of equity incentive plans	232,674	343,692
Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares	38,706	0
Weighted-average outstanding shares of common stock - diluted	48,238,098	47,766,088
Basic	$ 0.62	$ 0.45
Diluted	$ 0.61	$ 0.45
Share options excluded from the computation of diluted earnings per share	0

Net earnings available to common shareholders after adjustments for earnings allocated to participating securities

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of contingently issuable shares. Contingently issuable shares are those shares that are issuable for little or no cash contingent on certain conditions being met.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount of undistributed earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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