Condensed Consolidating Financials Condensed Income Statement (Details) - Scenario, Unspecified [Domain] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Total revenues	$ 176,038	$ 144,744	$ 337,291	$ 278,868
Interest expense (income), net	10,881	5,682	21,194	10,630
Other expense (income), net	88	(185)	(696)	(505)
Income Tax Expense (Benefit)	181	4,292	9,304	12,483
Cost of revenues	29,494	25,558	57,681	48,947
Gross Profit	146,544	119,186	279,610	229,921
Operating expenses:
Selling and Marketing Expense	40,421	35,329	78,011	68,288
Research and Development Expense	8,969	7,600	17,415	14,814
General and Administrative Expense	47,088	31,419	93,588	60,397
Operating Expenses	96,478	74,348	189,014	143,499
Income from operations	50,066	44,838	90,596	86,422
Income (Loss) from Subsidiaries, before Tax	0	0	0	0
Income (loss) before income taxes	39,097	39,341	70,098	76,297
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	38,916	35,049	60,794	63,814
Net Income (Loss) Attributable to Parent	38,916	35,049	60,794	63,814
j2 Global, Inc. [Member]
Total revenues	0	0	0	0
Interest expense (income), net	2,772	650	5,360	650
Other expense (income), net	(5)	0	(17)	0
Income Tax Expense (Benefit)	306	(379)	(2,075)	(379)
Cost of revenues	1	0	1	0
Gross Profit	(1)	0	(1)	0
Operating expenses:
Selling and Marketing Expense	0	0	0	0
Research and Development Expense	2	0	2	0
General and Administrative Expense	3,538	400	7,717	400
Operating Expenses	3,540	400	7,719	400
Income from operations	(3,541)	(400)	(7,720)	(400)
Income (Loss) from Subsidiaries, before Tax	45,530	0	71,782	0
Income (loss) before income taxes	39,222	(1,050)	58,719	(1,050)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	38,916	(671)	60,794	(671)
j2 Cloud Services, Inc. [Member]
Total revenues	56,547	65,313	111,166	116,507
Interest expense (income), net	5,791	5,095	10,899	10,198
Other expense (income), net	(28)	(40)	311	(71)
Income Tax Expense (Benefit)	(6,704)	(1,818)	3,744	1,325
Cost of revenues	15,414	19,051	30,942	39,004
Gross Profit	41,133	46,262	80,224	77,503
Operating expenses:
Selling and Marketing Expense	10,512	8,968	20,292	17,980
Research and Development Expense	3,763	3,471	7,618	7,091
General and Administrative Expense	9,011	7,646	15,861	17,215
Operating Expenses	23,286	20,085	43,771	42,286
Income from operations	17,847	26,177	36,453	35,217
Income (Loss) from Subsidiaries, before Tax	26,742	12,780	50,283	40,720
Income (loss) before income taxes	38,826	33,902	75,526	65,810
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	45,530	35,720	71,782	64,485
Non-Guarantor Subsidiaries [Member]
Total revenues	129,217	106,042	245,652	202,676
Interest expense (income), net	2,318	(63)	4,935	(218)
Other expense (income), net	121	(145)	(990)	(434)
Income Tax Expense (Benefit)	6,579	6,489	7,635	11,537
Cost of revenues	23,748	33,065	46,143	50,131
Gross Profit	105,469	72,977	199,509	152,545
Operating expenses:
Selling and Marketing Expense	29,966	26,414	57,841	50,435
Research and Development Expense	5,204	4,129	9,795	7,723
General and Administrative Expense	34,539	23,373	70,010	42,782
Operating Expenses	69,709	53,916	137,646	100,940
Income from operations	35,760	19,061	61,863	51,605
Income (Loss) from Subsidiaries, before Tax	0	0	0	0
Income (loss) before income taxes	33,321	19,269	57,918	52,257
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	26,742	12,780	50,283	40,720
Consolidation, Eliminations [Member]
Total revenues	(9,726)	(26,611)	(19,527)	(40,315)
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	(9,669)	(26,558)	(19,405)	(40,188)
Gross Profit	(57)	(53)	(122)	(127)
Operating expenses:
Selling and Marketing Expense	(57)	(53)	(122)	(127)
Research and Development Expense	0	0	0	0
General and Administrative Expense	0	0	0	0
Operating Expenses	(57)	(53)	(122)	(127)
Income from operations	0	0	0	0
Income (Loss) from Subsidiaries, before Tax	(72,272)	(12,780)	(122,065)	(40,720)
Income (loss) before income taxes	(72,272)	(12,780)	(122,065)	(40,720)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (72,272)	$ (12,780)	$ (122,065)	$ (40,720)