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ACQUISITIONS AND DISPOSITIONS - Pro Forma Results (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended	6 Months Ended
	Jul. 01, 2016	May 03, 2016	Jun. 30, 2016	Jun. 30, 2016
Pro Forma
Revenue			$ 132,444	$ 268,301
Net income (loss) attributable to ATN International, Inc. Stockholders			$ (463)	$ 5,596
Earnings per share: Basic (in dollars per share)			$ (0.03)	$ 0.35
Earnings per share: Diluted (in dollars per share)			$ (0.03)	$ 0.34
As reported
Pro Forma
Revenue			$ 99,991	$ 189,676
Net income (loss) attributable to ATN International, Inc. Stockholders			$ (3,086)	$ 3,034
Earnings per share: Basic (in dollars per share)			$ (0.19)	$ 0.19
Earnings per share: Diluted (in dollars per share)			$ (0.19)	$ 0.19
One Communications (formerly KeyTech)
Acquisition
Retirement of debt		$ 24,700
Viya (formerly Innovative)
Acquisition
Retirement of debt	$ 185,800
Viya (formerly Innovative) \| Term loans
Acquisition
Debt Instrument, Face Amount	$ 60,000
One Communications and Viya
Acquisition
Impairment charges			$ 1,100	$ 5,400