The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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GOODWILL AND INTANGIBLE ASSETS - Customer Relationships (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-lived intangible assets
Impairment of other intangibles	$ 300
U.S. Telecom
Finite-lived intangible assets
Other intangible assets	4,900
Customer relationships
Finite-lived intangible assets
Amortization	2,000	$ 400	$ 300
Customer relationships \| International Telecom
Future Amortization
2017	3,281
2018	2,411
2019	1,897
2020	1,528
2021	1,300
Thereafter	4,612
Total	15,029
Franchise Rights \| U.S. Telecom
Finite-lived intangible assets
Other intangible assets	3,000
Trade names \| U.S. Telecom
Finite-lived intangible assets
Other intangible assets	$ 1,900