Consolidated Statements Of Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Revenues	$ 371,396	$ 330,159	$ 255,394
Cost of revenues (including share-based compensation of $844, $982 and $1,217 in 2012, 2011 and 2010, respectively)	67,013	60,613	44,086
Gross profit	304,383	269,546	211,308
Operating expenses:
Sales and marketing (including share-based compensation of $1,543, $1,431 and $1,826 in 2012, 2011 and 2010, respectively)	62,825	59,066	46,332
Research, development and engineering (including share-based compensation of $459, $477 and $815, respectively)	18,624	16,373	12,827
General and administrative (including share-based compensation of $6,286, $6,103 and $7,079 in 2012, 2011 and 2010, respectively)	60,772	58,157	48,226
Total operating expenses	142,221	133,596	107,385
Operating earnings	162,162	135,950	103,923
Other Nonoperating Income	1,805	1,313	6,818
Other Nonoperating Expense	(9,045)	(147)	(104)
Interest and other income (expense), net	(7,240)	1,166	6,714
Earnings before income taxes	154,922	137,116	110,637
Income tax expense	33,259	22,350	27,590
Net earnings attributable to j2 Global, Inc. common shareholders	121,580	114,766	83,047
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	121,663	114,766	83,047
Net Income (Loss) Attributable to Noncontrolling Interest	$ 83	$ 0	$ 0
Net earnings per common share:
Basic	$ 2.63	$ 2.46	$ 1.86
Diluted	$ 2.61	$ 2.43	$ 1.81
Weighted average shares outstanding:
Basic	45,459,712	45,799,615	44,578,036
Diluted	45,781,658	46,384,848	45,941,843
Cash dividends paid per common share	$ 0.87	$ 0.41	$ 0.00