ACQUISITIONS AND DISPOSITIONS - Unaudited pro forma operating results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
ACQUISITIONS AND DISPOSITIONS
Amount of pre-Close debt, and associated interest removed from pro forma results		$ 164,600
Transaction debt included in pro forma results		283,000
Revenue	$ 172,019	124,510
Net Income attributable to ATN International, Inc. Stockholders	$ (948)	$ 2,706
Earnings Per Share
Basic (in dollars per share)	$ (0.13)	$ 0.17
Diluted (in dollars per share)	$ (0.13)	$ 0.17
Pro Forma
Revenue		$ 185,178
Net Income attributable to ATN International, Inc. Stockholders		1,034
Unaudited pro forma adjustments decrease of net income		$ 1,700
Earnings Per Share
Basic (in dollars per share)		$ (0.01)
Diluted (in dollars per share)		$ (0.01)