Condensed Consolidating Financials Condensed Statement of Cash Flows (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 92,573,000	$ 86,365,000
Depreciation and amortization	43,307,000	28,424,000
Accretion (Amortization) of Discounts and Premiums, Investments	983,000	1,323,000
Amortization of financing costs and discounts	2,828,000	456,000
Share-based Compensation	6,538,000	7,108,000
Excess Tax Benefit from Share-based Compensation, Operating Activities	(6,728,000)	(3,171,000)
Provision for doubtful accounts	3,278,000	2,565,000
Deferred income taxes	(2,954,000)	472,000
(Gain) loss on sale of available-for-sale investments	(69,000)	103,000
Increase (Decrease) in Accounts Receivable	1,267,000	(7,495,000)
Increase (Decrease) in Prepaid Expense and Other Assets	(4,124,000)	945,000
Increase (Decrease) in Other Operating Assets	(128,000)	182,000
Accounts payable and accrued expenses	(2,949,000)	4,035,000
Income taxes payable	7,565,000	(3,286,000)
Deferred revenue	(815,000)	13,049,000
Liability for uncertain tax positions	(8,071,000)	3,867,000
Other	(380,000)	(62,000)
Net Cash Provided by (Used in) Operating Activities	132,121,000	134,880,000
Maturity of certificates of deposit	14,520,000	42,615,000
Payments to Acquire Other Investments	0	(22,071,000)
Sales of available-for-sale investments	60,456,000	82,889,000
Payments to Acquire Available-for-sale Securities	(112,983,000)	(139,955,000)
Payments to Acquire Property, Plant, and Equipment	(7,755,000)	(11,116,000)
Proceeds from sale of assets	608,000	1,000
Payments to Acquire Businesses, Net of Cash Acquired	(118,238,000)	(81,566,000)
Payments to Acquire Intangible Assets	(4,806,000)	(2,784,000)
Payments to Acquire Interest in Subsidiaries and Affiliates	0	0
Payments for (Proceeds from) Other Investing Activities		0
Net Cash Provided by (Used in) Investing Activities	(168,198,000)	(131,987,000)
Proceeds from Issuance of Long-term Debt	402,500,000	0
Debt issuance costs	(11,527,000)	(47,000)
Payments for Repurchase of Common Stock	(5,473,000)	(4,513,000)
Issuance of common stock under employee stock purchase plan	199,000	161,000
Exercise of stock options	6,441,000	13,515,000
Payments of Dividends	(38,547,000)	(33,267,000)
Excess tax benefits from share-based compensation	6,728,000	3,171,000
Deferred payments for acquisitions	(14,316,000)	0
Proceeds from (Payments for) Other Financing Activities	(765,000)	(171,000)
Payments of Distributions to Affiliates	0	0
Net Cash Provided by (Used in) Financing Activities	345,240,000	(21,151,000)
Effect of exchange rate changes on cash and cash equivalents	(1,967,000)	(1,241,000)
Cash and Cash Equivalents, Period Increase (Decrease)	307,196,000	(19,499,000)
Cash and cash equivalents	514,997,000
j2 Global, Inc. [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(5,710,000)	0
Depreciation and amortization	0	0
Accretion (Amortization) of Discounts and Premiums, Investments	142,000	0
Amortization of financing costs and discounts	2,266,000	0
Share-based Compensation	2,191,000	0
Excess Tax Benefit from Share-based Compensation, Operating Activities	(1,925,000)	0
Provision for doubtful accounts	0	0
Deferred income taxes	4,614,000	0
(Gain) loss on sale of available-for-sale investments	(2,000)
Increase (Decrease) in Accounts Receivable	0	0
Increase (Decrease) in Prepaid Expense and Other Assets	(1,075,000)	0
Increase (Decrease) in Other Operating Assets	(896,000)	0
Accounts payable and accrued expenses	9,915,000	0
Income taxes payable	1,734,000	0
Deferred revenue	0	0
Liability for uncertain tax positions	0	0
Other	0	0
Net Cash Provided by (Used in) Operating Activities	11,254,000	0
Maturity of certificates of deposit	0	0
Payments to Acquire Other Investments	0	0
Sales of available-for-sale investments	2,005,000	0
Payments to Acquire Available-for-sale Securities	(58,591,000)	0
Payments to Acquire Property, Plant, and Equipment	0	0
Proceeds from sale of assets	0	0
Payments to Acquire Businesses, Net of Cash Acquired	0	0
Payments to Acquire Intangible Assets	0	0
Payments to Acquire Interest in Subsidiaries and Affiliates	0	0
Payments for (Proceeds from) Other Investing Activities		0
Net Cash Provided by (Used in) Investing Activities	(56,586,000)	0
Proceeds from Issuance of Long-term Debt	402,500,000
Debt issuance costs	(12,069,000)	0
Payments for Repurchase of Common Stock	(739,000)	0
Issuance of common stock under employee stock purchase plan	76,000	0
Exercise of stock options	1,193,000	0
Payments of Dividends	(13,267,000)	0
Excess tax benefits from share-based compensation	1,925,000	0
Deferred payments for acquisitions	0
Proceeds from (Payments for) Other Financing Activities	0	0
Payments of Distributions to Affiliates	(20,620,000)	0
Net Cash Provided by (Used in) Financing Activities	358,999,000	0
Effect of exchange rate changes on cash and cash equivalents	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	313,667,000	0
Cash and cash equivalents	313,667,000
j2 Cloud Services, Inc. [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	52,072,000	42,685,000
Depreciation and amortization	4,950,000	6,659,000
Accretion (Amortization) of Discounts and Premiums, Investments	677,000	948,000
Amortization of financing costs and discounts	562,000	456,000
Share-based Compensation	4,514,000	7,108,000
Excess Tax Benefit from Share-based Compensation, Operating Activities	(4,802,000)	(3,171,000)
Provision for doubtful accounts	1,395,000	1,016,000
Deferred income taxes	(2,657,000)	451,000
(Gain) loss on sale of available-for-sale investments	(18,000)
Increase (Decrease) in Accounts Receivable	(1,894,000)	(1,514,000)
Increase (Decrease) in Prepaid Expense and Other Assets	(2,197,000)	1,227,000
Increase (Decrease) in Other Operating Assets	(83,000)	(7,000)
Accounts payable and accrued expenses	(4,119,000)	(9,583,000)
Income taxes payable	2,822,000	(1,235,000)
Deferred revenue	(942,000)	14,331,000
Liability for uncertain tax positions	(8,069,000)	3,865,000
Other	(108,000)	(44,000)
Net Cash Provided by (Used in) Operating Activities	42,103,000	63,192,000
Maturity of certificates of deposit	8,210,000	30,270,000
Payments to Acquire Other Investments	0	(16,375,000)
Sales of available-for-sale investments	46,863,000	72,384,000
Payments to Acquire Available-for-sale Securities	(54,393,000)	(119,049,000)
Payments to Acquire Property, Plant, and Equipment	(925,000)	(4,134,000)
Proceeds from sale of assets	0	1,000
Payments to Acquire Businesses, Net of Cash Acquired	0	(2,305,000)
Payments to Acquire Intangible Assets	(2,871,000)	(1,828,000)
Payments to Acquire Interest in Subsidiaries and Affiliates	(23,822,000)	(12,498,000)
Payments for (Proceeds from) Other Investing Activities		3,281,000
Net Cash Provided by (Used in) Investing Activities	(26,938,000)	(50,253,000)
Proceeds from Issuance of Long-term Debt	0
Debt issuance costs	0	(47,000)
Payments for Repurchase of Common Stock	(4,733,000)	(4,514,000)
Issuance of common stock under employee stock purchase plan	123,000	161,000
Exercise of stock options	5,248,000	13,515,000
Payments of Dividends	(25,302,000)	(33,267,000)
Excess tax benefits from share-based compensation	4,803,000	3,171,000
Deferred payments for acquisitions	0
Proceeds from (Payments for) Other Financing Activities	(54,000)	0
Payments of Distributions to Affiliates	(14,861,000)	(18,120,000)
Net Cash Provided by (Used in) Financing Activities	(34,776,000)	(39,101,000)
Effect of exchange rate changes on cash and cash equivalents	4,000	(23,000)
Cash and Cash Equivalents, Period Increase (Decrease)	(19,607,000)	(26,185,000)
Cash and cash equivalents	14,799,000
Non-Guarantor Subsidiaries [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	46,211,000	43,680,000
Depreciation and amortization	38,357,000	21,765,000
Accretion (Amortization) of Discounts and Premiums, Investments	164,000	375,000
Amortization of financing costs and discounts	0	0
Share-based Compensation	(167,000)	0
Excess Tax Benefit from Share-based Compensation, Operating Activities	(1,000)	0
Provision for doubtful accounts	1,883,000	1,549,000
Deferred income taxes	(4,911,000)	21,000
(Gain) loss on sale of available-for-sale investments	(49,000)
Increase (Decrease) in Accounts Receivable	3,161,000	(5,981,000)
Increase (Decrease) in Prepaid Expense and Other Assets	(852,000)	(282,000)
Increase (Decrease) in Other Operating Assets	851,000	189,000
Accounts payable and accrued expenses	(8,745,000)	13,618,000
Income taxes payable	3,009,000	(2,051,000)
Deferred revenue	127,000	(1,282,000)
Liability for uncertain tax positions	(2,000)	2,000
Other	(272,000)	(18,000)
Net Cash Provided by (Used in) Operating Activities	78,764,000	71,688,000
Maturity of certificates of deposit	6,310,000	12,345,000
Payments to Acquire Other Investments	0	(5,696,000)
Sales of available-for-sale investments	11,588,000	10,505,000
Payments to Acquire Available-for-sale Securities	1,000	(20,906,000)
Payments to Acquire Property, Plant, and Equipment	(6,830,000)	(6,982,000)
Proceeds from sale of assets	608,000	0
Payments to Acquire Businesses, Net of Cash Acquired	(118,238,000)	(79,261,000)
Payments to Acquire Intangible Assets	(1,935,000)	(956,000)
Payments to Acquire Interest in Subsidiaries and Affiliates	0	0
Payments for (Proceeds from) Other Investing Activities		(3,281,000)
Net Cash Provided by (Used in) Investing Activities	(108,496,000)	(94,232,000)
Proceeds from Issuance of Long-term Debt	0
Debt issuance costs	542,000	0
Payments for Repurchase of Common Stock	(1,000)	1,000
Issuance of common stock under employee stock purchase plan	0	0
Exercise of stock options	0	0
Payments of Dividends	22,000	0
Excess tax benefits from share-based compensation	0	0
Deferred payments for acquisitions	(14,316,000)
Proceeds from (Payments for) Other Financing Activities	(711,000)	(171,000)
Payments of Distributions to Affiliates	59,303,000	30,618,000
Net Cash Provided by (Used in) Financing Activities	44,839,000	30,448,000
Effect of exchange rate changes on cash and cash equivalents	(1,971,000)	(1,218,000)
Cash and Cash Equivalents, Period Increase (Decrease)	13,136,000	6,686,000
Cash and cash equivalents	186,531,000
Consolidation, Eliminations [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	0	0
Depreciation and amortization	0	0
Accretion (Amortization) of Discounts and Premiums, Investments	0	0
Amortization of financing costs and discounts	0	0
Share-based Compensation	0	0
Excess Tax Benefit from Share-based Compensation, Operating Activities	0	0
Provision for doubtful accounts	0	0
Deferred income taxes	0	0
(Gain) loss on sale of available-for-sale investments	0
Increase (Decrease) in Accounts Receivable	0	0
Increase (Decrease) in Prepaid Expense and Other Assets	0	0
Increase (Decrease) in Other Operating Assets	0	0
Accounts payable and accrued expenses	0	0
Income taxes payable	0	0
Deferred revenue	0	0
Liability for uncertain tax positions	0	0
Other	0	0
Net Cash Provided by (Used in) Operating Activities	0	0
Maturity of certificates of deposit	0	0
Payments to Acquire Other Investments	0	0
Sales of available-for-sale investments	0	0
Payments to Acquire Available-for-sale Securities	0	0
Payments to Acquire Property, Plant, and Equipment	0	0
Proceeds from sale of assets	0	0
Payments to Acquire Businesses, Net of Cash Acquired	0	0
Payments to Acquire Intangible Assets	0	0
Payments to Acquire Interest in Subsidiaries and Affiliates	23,822,000	12,498,000
Payments for (Proceeds from) Other Investing Activities		0
Net Cash Provided by (Used in) Investing Activities	23,822,000	12,498,000
Proceeds from Issuance of Long-term Debt	0
Debt issuance costs	0	0
Payments for Repurchase of Common Stock	0	0
Issuance of common stock under employee stock purchase plan	0	0
Exercise of stock options	0	0
Payments of Dividends	0	0
Excess tax benefits from share-based compensation	0	0
Deferred payments for acquisitions	0
Proceeds from (Payments for) Other Financing Activities	0	0
Payments of Distributions to Affiliates	(23,822,000)	(12,498,000)
Net Cash Provided by (Used in) Financing Activities	(23,822,000)	(12,498,000)
Effect of exchange rate changes on cash and cash equivalents	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0	0
Cash and cash equivalents	$ 0