EQUITY (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Stockholders' equity
Equity, beginning of period	$ 809,169	$ 761,724
Stock-based compensation	1,666	1,728
Comprehensive income:
Net income	11,584	10,798
Pension	513
Reclassifications of gains on sale of marketable securities to net income	(289)
Unrealized loss on marketable securities	(41)
Foreign currency translation adjustment	1,930	3
Comprehensive income	13,697	10,801
Issuance of common stock upon exercise of stock options	95	582
Dividends declared on common stock	(5,460)	(5,166)
Distributions to non-controlling interests	(2,888)	(3,090)
Investments made by non-controlling interests	69
Loss on deconsolidation of subsidiary	529
Repurchase of non-controlling interests	(819)
Purchase of treasury stock	(2,215)	(2,348)
Equity, end of period	813,953	764,231
Accounting Standards Update 2016-09
Comprehensive income:
Change in accounting method- adoption of ASC 2016-09	110
Total ATNI Stockholders' Equity
Stockholders' equity
Equity, beginning of period	677,055	680,299
Stock-based compensation	1,666	1,728
Comprehensive income:
Net income	6,859	6,120
Pension	513
Reclassifications of gains on sale of marketable securities to net income	(289)
Unrealized loss on marketable securities	(41)
Foreign currency translation adjustment	1,930	3
Comprehensive income	8,972	6,123
Issuance of common stock upon exercise of stock options	95	582
Dividends declared on common stock	(5,460)	(5,166)
Repurchase of non-controlling interests	(670)
Purchase of treasury stock	(2,215)	(2,348)
Equity, end of period	679,553	681,218
Total ATNI Stockholders' Equity | Accounting Standards Update 2016-09
Comprehensive income:
Change in accounting method- adoption of ASC 2016-09	110
Non-Controlling Interests
Stockholders' equity
Equity, beginning of period	132,114	81,425
Comprehensive income:
Net income	4,725	4,678
Comprehensive income	4,725	4,678
Distributions to non-controlling interests	(2,888)	(3,090)
Investments made by non-controlling interests	69
Loss on deconsolidation of subsidiary	529
Repurchase of non-controlling interests	(149)
Equity, end of period	$ 134,400	$ 83,013