Condensed Consolidating Financials Condensed Comprehensive Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Comprehensive (Income) Loss, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	$ 0	$ (13)	$ 0	$ (35)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	28,759	27,627	92,573	86,365
Net Income (Loss) Attributable to Noncontrolling Interest	0	(179)	0	(403)
Foreign currency translation adjustment, net of tax (benefit)	(6,977)	1,590	(4,806)	(526)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(3,006)	4,259	(2,761)	9,260
Other Comprehensive Income (Loss), Net of Tax	(9,983)	5,849	(7,567)	8,734
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	18,776	33,476	85,006	95,099
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	18,776	33,668	85,006	95,537
j2 Global, Inc. [Member]
Other Comprehensive (Income) Loss, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest		0		0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(5,039)	0	(5,710)	0
Net Income (Loss) Attributable to Noncontrolling Interest		0		0
Foreign currency translation adjustment, net of tax (benefit)	0	0	0	0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	64	0	64	0
Other Comprehensive Income (Loss), Net of Tax	64	0	64	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		0		0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(4,975)	0	(5,646)	0
j2 Cloud Services, Inc. [Member]
Other Comprehensive (Income) Loss, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest		0		0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	28,306	20,313	52,072	42,685
Net Income (Loss) Attributable to Noncontrolling Interest		0		0
Foreign currency translation adjustment, net of tax (benefit)	2,300	(586)	1,644	(159)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(3,068)	4,247	(2,834)	5,767
Other Comprehensive Income (Loss), Net of Tax	(768)	3,661	(1,190)	5,608
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		23,974		48,293
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	27,538	23,974	50,882	48,293
Non-Guarantor Subsidiaries [Member]
Other Comprehensive (Income) Loss, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest		(13)		(35)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	5,492	7,314	46,211	43,680
Net Income (Loss) Attributable to Noncontrolling Interest		0		0
Foreign currency translation adjustment, net of tax (benefit)	(9,277)	2,176	(6,450)	(367)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(2)	12	9	3,493
Other Comprehensive Income (Loss), Net of Tax	(9,279)	2,188	(6,441)	3,126
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		9,502		46,806
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(3,787)	9,515	39,770	46,841
Consolidation, Eliminations [Member]
Other Comprehensive (Income) Loss, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest		0		0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	0	0	0	0
Net Income (Loss) Attributable to Noncontrolling Interest		(179)		(403)
Foreign currency translation adjustment, net of tax (benefit)	0	0	0	0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		0		0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 0	$ 179	$ 0	$ 403