SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment reporting
Number of reportable segments | segment	3
Revenue
Revenue	$ 104,475	$ 128,115
Depreciation and amortization	21,305	22,494
Non-cash stock-based compensation	1,576	1,666
Operating income (loss)	4,209	17,756
Segment Assets
Cash, Cash equivalents, and Investments	206,409		$ 215,032
Total current assets	303,355		342,928
Fixed assets, net	673,488		643,146
Goodwill	63,970		63,970
Total assets	1,196,818		1,205,605
Total current liabilities	168,891		161,705
Total debt	154,895		155,792
Capital Expenditures
Capital expenditures	51,892	45,702
Hurricane rebuild capital expenditures	30,851
Hurricane insurance proceeds	34,606
Wireless
Revenue
Revenue	50,548	58,925
Wireline
Revenue
Revenue	48,096	64,159
Renewable Energy
Revenue
Revenue	5,831	5,031
Corporate and Other
Revenue
Depreciation and amortization	1,347	1,372
Non-cash stock-based compensation	1,518	1,508
Operating income (loss)	(8,591)	(10,230)
Segment Assets
Cash, Cash equivalents, and Investments	113,319		76,627
Total current assets	129,302		93,497
Fixed assets, net	18,168		17,752
Total assets	220,213		184,050
Total current liabilities	15,077		13,816
Capital Expenditures
Capital expenditures	2,291	1,204
U.S. Telecom | Operating segments
Revenue
Revenue	28,499	43,793
Depreciation and amortization	6,513	6,551
Operating income (loss)	5,224	16,617
Segment Assets
Cash, Cash equivalents, and Investments	14,605		19,585
Total current assets	40,105		40,975
Fixed assets, net	96,961		99,462
Goodwill	35,269		35,269
Total assets	196,814		200,142
Total current liabilities	40,848		41,248
Capital Expenditures
Capital expenditures	4,751	6,044
U.S. Telecom | Operating segments | Wireless
Revenue
Revenue	27,401	37,702
U.S. Telecom | Operating segments | Wireline
Revenue
Revenue	1,098	6,091
International Telecom segment | Operating segments
Revenue
Revenue	70,145	79,291
Depreciation and amortization	11,671	13,117
Non-cash stock-based compensation	29	129
Operating income (loss)	5,640	9,926
Segment Assets
Cash, Cash equivalents, and Investments	65,438		110,700
Total current assets	115,348		190,396
Fixed assets, net	402,093		367,485
Goodwill	25,421		25,421
Total assets	588,713		629,007
Total current liabilities	95,655		91,887
Total debt	93,676		94,577
Capital Expenditures
Capital expenditures	43,996	16,666
International Telecom segment | Operating segments | Wireless
Revenue
Revenue	23,147	21,223
International Telecom segment | Operating segments | Wireline
Revenue
Revenue	46,998	58,068
Renewable Energy | Operating segments
Revenue
Revenue	5,831	5,031
Depreciation and amortization	1,774	1,454
Non-cash stock-based compensation	29	29
Operating income (loss)	1,936	1,443
Segment Assets
Cash, Cash equivalents, and Investments	13,047		8,120
Total current assets	18,600		18,060
Fixed assets, net	156,266		158,447
Goodwill	3,280		3,280
Total assets	191,078		192,406
Total current liabilities	17,311		14,754
Total debt	61,219		$ 61,215
Capital Expenditures
Capital expenditures	854	21,788
Renewable Energy | Operating segments | Renewable Energy
Revenue
Revenue	$ 5,831	$ 5,031