QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly financial data
Total revenue	$ 128,531	$ 138,795	$ 99,991	$ 89,686	$ 82,916	$ 96,782	$ 90,326	$ 85,345		$ 457,003	$ 355,369	$ 336,347
Operating expenses	118,620	116,714	98,079	73,793	74,735	74,258	61,594	66,187		407,206	276,774	250,771
Income from operations	9,911	22,081	1,912	15,893	8,181	22,524	28,732	19,158		49,797	78,595	85,576
Other income (expense), net	(2,321)	(785)	(853)	(464)	(418)	(742)	(706)	(20,528)		(4,423)	(22,394)	592
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	7,590	21,296	1,059	15,429	7,763	21,782	28,026	(1,370)		45,374	56,201	86,168
Income taxes	3,982	9,602	2,945	4,631	1,482	10,134	13,008	(487)		21,160	24,137	28,148
INCOME FROM CONTINUING OPERATIONS	3,608	11,694	(1,886)	10,798	6,281	11,648	15,018	(883)		24,214	32,064	58,020
Income from discontinued operations:
Gain on sale of discontinued operations, net of tax					702			389			1,092	1,102
Income from discontinued operations, net of tax					702			390			1,092	1,102
NET INCOME	3,608	11,694	(1,886)	10,798	6,983	11,648	15,018	(493)		24,214	33,156	59,122
Net income attributable to non-controlling interests, net of tax:
Continuing operations	(1,712)	(4,523)	(1,200)	(4,678)	(2,799)	(5,072)	(5,568)	(2,777)
NET INCOME ATTRIBUTABLE TO ATN INTERNATIONAL, INC. STOCKHOLDERS	$ 1,896	$ 7,171	$ (3,086)	$ 6,120	$ 4,184	$ 6,576	$ 9,450	$ (3,270)		$ 12,101	$ 16,940	$ 48,152
NET INCOME PER WEIGHTED AVERAGE BASIC SHARE ATTRIBUTABLE TO ATN INTERNATIONAL, INC. STOCKHOLDERS:
Continuing operations (in dollars per share)	$ 0.12	$ 0.44	$ (0.19)	$ 0.38	$ 0.17	$ 0.41	$ 0.59	$ (0.18)		$ 0.75	$ 0.99	$ 2.96
Discontinued operations:
Discontinued operations (in dollars per share)								0.07
Total discontinued operations (in dollars per share)								0.07			0.07	0.07
Total (in dollars per share)	0.12	0.44	(0.19)	0.38	0.17	0.41	0.59	(0.11)		0.75	1.06	3.03
NET INCOME PER WEIGHTED AVERAGE DILUTED SHARE ATTRIBUTABLE TO ATN INTERNATIONAL, INC. STOCKHOLDERS:
Continuing operations (in dollars per share)	0.12	0.44	(0.19)	0.38	0.16	0.41	0.59	(0.18)		0.75	0.98	2.94
Discontinued operations:
Discontinued operations (in dollars per share)								0.07
Total discontinued operations (in dollars per share)								0.07			0.07	0.07
Total (in dollars per share)	$ 0.12	$ 0.44	$ (0.19)	$ 0.38	$ 0.16	$ 0.41	$ 0.59	$ (0.11)		$ 0.75	$ 1.05	$ 3.01
Additional information:
Reclassification, decrease (increase) to expense	$ (800)				$ 700
Tax basis differences and expense recognition adjustment						$ 700
International Telecom | Operating Expense
Additional information:
Understatement of expense									$ 300
Renewable energy | Revenue
Additional information:
Understatement of revenue									$ 500