Condensed Consolidating Financials Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 187,409	$ 123,950	$ 242,755	$ 255,530
Short-term investments	65	60
Accounts receivable, net of allowances of $8,137 and $7,988, respectively	172,062	199,871
Prepaid expenses and other current assets	24,177	24,118
Due from Affiliate, Current	0	0
Total current assets	383,713	347,999
Property and equipment, net	69,714	68,094
Trade names, net	113,339	115,853
Patent and patent licenses, net	12,553	13,928
Customer Relationships, Net	204,920	208,155
Goodwill	1,138,700	1,122,810
Other purchased intangibles, net	166,388	173,755
Investments in and Advances to Affiliates, Amount of Equity	0	0
Deferred tax assets, non-current	6,912	5,289
Other assets	6,313	6,445
Total assets	2,102,552	2,062,328
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable and accrued expenses	145,927	178,071
Income taxes payable	21,599	16,753
Deferred revenue, current	85,431	80,384
Line of credit	224,123	178,817
Other current liabilities	34	64
Due to Affiliate, Current	0	0
Total current liabilities	477,114	454,089
Long-term debt	604,273	601,746
Liability for uncertain tax positions	47,178	46,537
Deferred income taxes, non-current	39,752	40,357
Deferred revenue, non-current	822	1,588
Other long-term liabilities	2,987	3,475
Total liabilities	1,172,126	1,147,792
Commitments and contingencies	0	0
Common Stock, Value, Issued	475	474
Additional paid-in capital	312,468	308,329
Retained earnings (accumulated deficit)	668,550	660,382
Accumulated Other Comprehensive Income (Loss), Net of Tax	(51,067)	(54,649)
Stockholders' Equity Attributable to Parent	930,426	914,536
Total liabilities and stockholders’ equity	2,102,552	2,062,328
Series A Preferred Stock [Member]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Preferred stock, $0.01 par value	0	0
j2 Global, Inc. [Member]
ASSETS
Cash and cash equivalents	15,150	23,935	36,637	55,516
Short-term investments	0	0
Accounts receivable, net of allowances of $8,137 and $7,988, respectively	1	0
Prepaid expenses and other current assets	38,296	25,922
Due from Affiliate, Current	679,103	635,740
Total current assets	732,550	685,597
Property and equipment, net	0	0
Trade names, net	0	0
Patent and patent licenses, net	0	0
Customer Relationships, Net	0	0
Goodwill	0	0
Other purchased intangibles, net	0	0
Investments in and Advances to Affiliates, Amount of Equity	1,121,423	1,091,412
Deferred tax assets, non-current	0	1,346
Other assets	0	0
Total assets	1,853,973	1,778,355
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable and accrued expenses	6,697	4,545
Income taxes payable	0	0
Deferred revenue, current	0	0
Line of credit	224,123	178,817
Other current liabilities	0	0
Due to Affiliate, Current	303,492	296,658
Total current liabilities	534,312	480,020
Long-term debt	357,462	355,143
Liability for uncertain tax positions	0	0
Deferred income taxes, non-current	31,738	28,687
Deferred revenue, non-current	0	0
Other long-term liabilities	1,107	1,040
Total liabilities	924,619	864,890
Commitments and contingencies	0	0
Preferred stock, $0.01 par value	0	0
Common Stock, Value, Issued	475	474
Additional paid-in capital	468,359	464,220
Retained earnings (accumulated deficit)	460,520	448,771
Accumulated Other Comprehensive Income (Loss), Net of Tax	0	0
Stockholders' Equity Attributable to Parent	929,354	913,465
Total liabilities and stockholders’ equity	1,853,973	1,778,355
j2 Cloud Services, LLC [Member]
ASSETS
Cash and cash equivalents	34,395	22,949	4,536	9,975
Short-term investments	0	0
Accounts receivable, net of allowances of $8,137 and $7,988, respectively	10,143	11,464
Prepaid expenses and other current assets	1,766	2,266
Due from Affiliate, Current	299,743	281,078
Total current assets	346,047	317,757
Property and equipment, net	6,088	6,318
Trade names, net	10,439	10,097
Patent and patent licenses, net	565	601
Customer Relationships, Net	10,810	2,519
Goodwill	70,480	58,310
Other purchased intangibles, net	6,944	4,804
Investments in and Advances to Affiliates, Amount of Equity	751,821	730,153
Deferred tax assets, non-current	32,667	26,667
Other assets	422	443
Total assets	1,236,283	1,157,669
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable and accrued expenses	44,117	28,179
Income taxes payable	94,709	82,795
Deferred revenue, current	20,324	19,277
Line of credit	0	0
Other current liabilities	0	0
Due to Affiliate, Current	0	11
Total current liabilities	159,150	130,262
Long-term debt	246,811	246,604
Liability for uncertain tax positions	41,833	41,259
Deferred income taxes, non-current	0	0
Deferred revenue, non-current	822	1,588
Other long-term liabilities	559	505
Total liabilities	449,175	420,218
Commitments and contingencies	0	0
Preferred stock, $0.01 par value	0	0
Common Stock, Value, Issued	0	0
Additional paid-in capital	89,066	89,066
Retained earnings (accumulated deficit)	697,822	648,233
Accumulated Other Comprehensive Income (Loss), Net of Tax	220	152
Stockholders' Equity Attributable to Parent	787,108	737,451
Total liabilities and stockholders’ equity	1,236,283	1,157,669
Non-Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	137,864	77,066	201,582	190,039
Short-term investments	65	60
Accounts receivable, net of allowances of $8,137 and $7,988, respectively	161,919	188,498
Prepaid expenses and other current assets	22,295	21,246
Due from Affiliate, Current	149,971	166,210
Total current assets	472,114	453,080
Property and equipment, net	63,626	61,776
Trade names, net	102,900	105,756
Patent and patent licenses, net	11,988	13,327
Customer Relationships, Net	194,110	205,636
Goodwill	1,068,220	1,064,500
Other purchased intangibles, net	159,444	168,951
Investments in and Advances to Affiliates, Amount of Equity	(1,073)	(1,071)
Deferred tax assets, non-current	1,752	2,171
Other assets	5,891	6,002
Total assets	2,078,972	2,080,128
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable and accrued expenses	133,294	170,754
Income taxes payable	0	0
Deferred revenue, current	65,107	61,107
Line of credit	0	0
Other current liabilities	34	64
Due to Affiliate, Current	752,214	720,317
Total current liabilities	950,649	952,242
Long-term debt	0	(1)
Liability for uncertain tax positions	5,345	5,278
Deferred income taxes, non-current	35,521	36,565
Deferred revenue, non-current	0	0
Other long-term liabilities	1,321	1,930
Total liabilities	992,836	996,014
Commitments and contingencies	0	0
Preferred stock, $0.01 par value	0	0
Common Stock, Value, Issued	0	0
Additional paid-in capital	424,399	424,399
Retained earnings (accumulated deficit)	713,024	714,516
Accumulated Other Comprehensive Income (Loss), Net of Tax	(51,287)	(54,801)
Stockholders' Equity Attributable to Parent	1,086,136	1,084,114
Total liabilities and stockholders’ equity	2,078,972	2,080,128
Consolidation, Eliminations [Member]
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Short-term investments	0	0
Accounts receivable, net of allowances of $8,137 and $7,988, respectively	(1)	(91)
Prepaid expenses and other current assets	(38,180)	(25,316)
Due from Affiliate, Current	(1,128,817)	(1,083,028)
Total current assets	(1,166,998)	(1,108,435)
Property and equipment, net	0	0
Trade names, net	0	0
Patent and patent licenses, net	0	0
Customer Relationships, Net	0	0
Goodwill	0	0
Other purchased intangibles, net	0	0
Investments in and Advances to Affiliates, Amount of Equity	(1,872,171)	(1,820,494)
Deferred tax assets, non-current	(27,507)	(24,895)
Other assets	0	0
Total assets	(3,066,676)	(2,953,824)
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable and accrued expenses	(38,181)	(25,407)
Income taxes payable	(73,110)	(66,042)
Deferred revenue, current	0	0
Line of credit	0	0
Other current liabilities	0	0
Due to Affiliate, Current	(1,055,706)	(1,016,986)
Total current liabilities	(1,166,997)	(1,108,435)
Long-term debt	0	0
Liability for uncertain tax positions	0	0
Deferred income taxes, non-current	(27,507)	(24,895)
Deferred revenue, non-current	0	0
Other long-term liabilities	0	0
Total liabilities	(1,194,504)	(1,133,330)
Commitments and contingencies	0	0
Preferred stock, $0.01 par value	0	0
Common Stock, Value, Issued	0	0
Additional paid-in capital	(669,356)	(669,356)
Retained earnings (accumulated deficit)	(1,202,816)	(1,151,138)
Accumulated Other Comprehensive Income (Loss), Net of Tax	0	0
Stockholders' Equity Attributable to Parent	(1,872,172)	(1,820,494)
Total liabilities and stockholders’ equity	$ (3,066,676)	$ (2,953,824)