EQUITY (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Stockholders' equity
Equity, beginning of period			$ 809,169	$ 761,724
Stock-based compensation			3,764	3,626
Comprehensive income:
Net income	$ 10,909	$ (1,886)	22,494	8,911
Pension			513
Reclassifications of gains on sale of marketable securities to net income	(755)		(1,044)
Unrealized loss on marketable securities	(90)		(130)
Foreign currency translation adjustment	302	(40)	2,232	(36)
Comprehensive income	10,366	(1,926)	24,065	8,875
Issuance of common stock upon exercise of stock options			401	585
Dividends declared on common stock			(10,951)	(10,330)
Distributions to non-controlling interests			(3,491)	(4,404)
Investments made by non-controlling interests			123	21,904
Acquisition of One Communications				32,903
Loss on deconsolidation of subsidiary			529
Repurchase of non-controlling interests			(955)	(7,045)
Purchase of treasury stock			(2,314)	(2,407)
Equity, end of period	820,450	805,431	820,450	805,431
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			3,764	3,626
Comprehensive income:
Net income			12,743	3,034
Pension			513
Reclassifications of gains on sale of marketable securities to net income			(1,044)
Unrealized loss on marketable securities			(130)
Foreign currency translation adjustment			2,232	(36)
Comprehensive income			14,314	2,998
Issuance of common stock upon exercise of stock options			401	585
Dividends declared on common stock			(10,951)	(10,330)
Repurchase of non-controlling interests			(670)	(4,105)
Purchase of treasury stock			(2,314)	(2,407)
Equity, end of period	681,709	670,666	681,709	670,666
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			9,751	5,877
Comprehensive income			9,751	5,877
Distributions to non-controlling interests			(3,491)	(4,404)
Investments made by non-controlling interests			123	21,904
Acquisition of One Communications				32,903
Loss on deconsolidation of subsidiary			529
Repurchase of non-controlling interests			(285)	(2,940)
Equity, end of period	$ 138,741	$ 134,765	$ 138,741	134,765
Non-controlling interest's cash contribution to subsidiary				$ 21,700