DISCONTINUED OPERATIONS - SALE OF U.S. RETAIL WIRELESS BUSINESS (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 20, 2013
Proceeds:
Current assets		$ 468,492		$ 451,374	$ 468,492	$ 451,374
Property, plant and equipment, net		373,503		369,582	373,503	369,582
Telecommunication licenses, net		43,468		44,090	43,468	44,090
Other assets		7,489		7,519	7,489	7,519
Liabilities sold:
Current liabilities		(84,355)		(104,069)	(84,355)	(104,069)
Other liabilities		(26,944)		(19,619)	(26,944)	(19,619)
Net gain on sale		702	$ 389	1,102	1,092	1,102	$ 307,102
Restricted cash, current		824		39,703	824	39,703
Restricted cash, long-term		5,477		5,475	5,477	5,475
Impairment of intangible assets					0	0
Minority shareholders' interests in sale of operations							28,899
Amount distributed to minority shareholders					16,514	16,331	26,155
Amount included in non-controlling interests		81,425		60,960	81,425	60,960
Revenues and income from discontinued operations
Revenue from discontinued operations								$ 299,519
Income from discontinued operations, net of tax expense of $2,512							5,166	$ 5,166
AT&T Mobility | Trade names | Alltel Wireless
Liabilities sold:
Impairment of intangible assets						11,900
Alltel Sale | AT&T Mobility
SALE OF U.S. RETAIL WIRELESS BUSINESS
Consideration for sale of operations in all-cash transaction									$ 780,000
Proceeds:
Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds									780,000
Received						702,000
Escrowed						78,000
Working capital						16,828
Adjusted proceeds						796,828
Current assets				51,597		51,597
Property, plant and equipment, net				190,970		190,970
Telecommunication licenses, net				50,553		50,553
Other intangible assets				37,434		37,434
Other assets				13,202		13,202
Liabilities sold:
Current liabilities				(40,674)		(40,674)
Other liabilities				(22,796)		(22,796)
Net assets sold or impaired				280,286		280,286
Less: Transaction related costs						(13,517)
Pre-tax gain						503,025
Less: Income taxes at effective rate						195,923
Net gain on sale						307,102
Additional gain (loss) on sale of assets					1,100	1,100
Restricted cash, current		39,000			39,000
Indemnity escrow released	$ 39,000
Minority shareholders' interests in sale of operations					28,900
Amount distributed to minority shareholders					4,100	5,800	$ 18,900
Amount included in non-controlling interests		$ 400		$ 4,500	$ 400	4,500
Revenues and income from discontinued operations
Income from discontinued operations, tax expense (benefit)						$ 2,512
Alltel Sale | AT&T Mobility | Alltel Wireless
SALE OF U.S. RETAIL WIRELESS BUSINESS
Consideration for sale of operations in all-cash transaction									780,000
Proceeds:
Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds									$ 780,000