Basis Of Presentation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Revenue	$ 113,617	$ 86,652
Net income attributable to j2 Global, Inc. common shareholders	$ 22,922	$ 28,539
Basic earnings per share	$ 0.50	$ 0.61
Diluted earnings per share	$ 0.49	$ 0.60

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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+ Details

- Definition

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.

+ References+ Details

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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-Glossary Net Income

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-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph A7

-Appendix A

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Reference 16: http://www.xbrl.org/2003/role/presentationRef

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+ Details