Condensed Consolidating Financials Condensed Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Total revenues	$ 178,701	$ 153,018	$ 515,992	$ 431,886
Interest expense (income), net	10,259	10,123	31,453	20,753
Other expense (income), net	1,086	251	390	(254)
Income Tax Expense (Benefit)	7,013	7,345	16,317	19,828
Cost of revenues	30,669	28,044	88,350	76,991
Gross Profit	148,032	124,974	427,642	354,895
Operating expenses:
Selling and Marketing Expense	38,808	37,047	116,819	105,335
Research and Development Expense	8,289	7,637	25,704	22,451
General and Administrative Expense	45,202	33,812	138,790	94,209
Operating Expenses	92,299	78,496	281,313	221,995
Income from operations	55,733	46,478	146,329	132,900
Income (Loss) from Subsidiaries, before Tax	0	0	0	0
Income (loss) before income taxes	44,388	36,104	114,486	112,401
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	37,375	28,759	98,169	92,573
Net Income (Loss) Attributable to Parent	37,375	28,759	98,169	92,573
j2 Global, Inc. [Member]
Total revenues	0	0	0	0
Interest expense (income), net	3,293	5,136	8,651	5,786
Other expense (income), net	(2)	(2)	(20)	(2)
Income Tax Expense (Benefit)	(3,117)	(3,158)	(5,192)	(3,537)
Cost of revenues	(1)	0	0	0
Gross Profit	1	0	0	0
Operating expenses:
Selling and Marketing Expense	0	0	0	0
Research and Development Expense	(2)	0	0	0
General and Administrative Expense	3,714	3,063	11,434	3,463
Operating Expenses	3,712	3,063	11,434	3,463
Income from operations	(3,711)	(3,063)	(11,434)	(3,463)
Income (Loss) from Subsidiaries, before Tax	41,260	33,798	113,042	98,283
Income (loss) before income taxes	34,258	25,601	92,977	89,036
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	37,375	28,759	98,169	92,573
j2 Cloud Services, Inc. [Member]
Total revenues	56,753	52,960	167,919	169,467
Interest expense (income), net	5,179	5,116	16,079	15,314
Other expense (income), net	37	78	347	6
Income Tax Expense (Benefit)	3,862	3,458	7,606	4,783
Cost of revenues	29,375	(3,275)	60,317	35,729
Gross Profit	27,378	56,235	107,602	133,738
Operating expenses:
Selling and Marketing Expense	9,684	9,168	29,976	27,149
Research and Development Expense	3,646	3,320	11,264	10,411
General and Administrative Expense	5,067	6,789	20,928	24,003
Operating Expenses	18,397	19,277	62,168	61,563
Income from operations	8,981	36,958	45,434	72,175
Income (Loss) from Subsidiaries, before Tax	41,357	5,492	91,640	46,211
Income (loss) before income taxes	45,122	37,256	120,648	103,066
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	41,260	33,798	113,042	98,283
Non-Guarantor Subsidiaries [Member]
Total revenues	148,648	90,854	394,300	293,530
Interest expense (income), net	1,787	(129)	6,723	(347)
Other expense (income), net	1,051	175	63	(258)
Income Tax Expense (Benefit)	6,268	7,045	13,903	18,582
Cost of revenues	27,948	22,060	74,091	72,191
Gross Profit	120,700	68,794	320,209	221,339
Operating expenses:
Selling and Marketing Expense	29,171	27,934	87,012	78,368
Research and Development Expense	4,645	4,317	14,440	12,040
General and Administrative Expense	36,421	23,960	106,428	66,743
Operating Expenses	70,237	56,211	207,880	157,151
Income from operations	50,463	12,583	112,329	64,188
Income (Loss) from Subsidiaries, before Tax	0	0	0	0
Income (loss) before income taxes	47,625	12,537	105,543	64,793
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	41,357	5,492	91,640	46,211
Consolidation, Eliminations [Member]
Total revenues	(26,700)	9,204	(46,227)	(31,111)
Interest expense (income), net	0	0	0	0
Other expense (income), net	0	0	0	0
Income Tax Expense (Benefit)	0	0	0	0
Cost of revenues	(26,653)	9,259	(46,058)	(30,929)
Gross Profit	(47)	(55)	(169)	(182)
Operating expenses:
Selling and Marketing Expense	(47)	(55)	(169)	(182)
Research and Development Expense	0	0	0	0
General and Administrative Expense	0	0	0	0
Operating Expenses	(47)	(55)	(169)	(182)
Income from operations	0	0	0	0
Income (Loss) from Subsidiaries, before Tax	(82,617)	(39,290)	(204,682)	(144,494)
Income (loss) before income taxes	(82,617)	(39,290)	(204,682)	(144,494)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (82,617)	$ (39,290)	$ (204,682)	$ (144,494)