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ACQUISITIONS AND DISPOSITIONS - Pro Forma Results (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Jul. 01, 2016	May 03, 2016	Mar. 31, 2016
Pro Forma
Revenue			$ 135,859
Net income (loss) attributable to ATN International, Inc. Stockholders			$ 6,061
Earnings per share: Basic (in dollars per share)			$ 0.38
Earnings per share: Diluted (in dollars per share)			$ 0.37
As reported
Pro Forma
Revenue			$ 89,686
Net income (loss) attributable to ATN International, Inc. Stockholders			$ 6,120
Earnings per share: Basic (in dollars per share)			$ 0.38
Earnings per share: Diluted (in dollars per share)			$ 0.38
One Communications (formerly KeyTech)
Business Acquisition [Line Items]
Retirement of debt		$ 24,700
Viya (formerly Innovative)
Business Acquisition [Line Items]
Retirement of debt	$ 185,800
Viya (formerly Innovative) \| Term loans
Business Acquisition [Line Items]
Debt Instrument, Face Amount	$ 60,000
One Communications (formerly KeyTech)
Business Acquisition [Line Items]
Impairment charges			$ 4,300