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ACQUISITIONS AND DISPOSITIONS - Purchase Price Allocation - Viya (Details) - USD ($) $ in Thousands		3 Months Ended
	Jul. 01, 2016	Dec. 31, 2016	Jun. 30, 2017
Purchase price allocation:
Goodwill		$ 62,873	$ 62,873
Viya (formerly Innovative)
Consideration Transferred
Purchase price	$ 145,000
Purchase price adjustments	5,300
Cash consideration	51,900
Pension funding required by acquisition		22,500
Total consideration	111,860
Restricted cash	5,300
Working capital adjustments and pension funding		$ 27,800
Total value to allocate
Total consideration	111,860
Non-controlling interests	221
Value to allocate	112,081
Purchase price allocation:
Cash	4,229
Accounts receivable	6,553
Materials & supplies	6,533
Other current assets	1,927
Property, plant and equipment	108,284
Telecommunication licenses	7,623
Goodwill	20,586
Intangible assets	7,800
Other Assets	4,394
Accounts payable and accrued liabilities	(15,971)
Advance payments and deposits	(7,793)
Deferred tax liability	(2,935)
Pension liability	(29,149)
Net assets acquired	112,081
Viya (formerly Innovative) \| Innovative Pension Benefit
Consideration Transferred
Restricted cash			$ 5,100
Viya (formerly Innovative) \| Term loans
Consideration Transferred
Debt instrument, face amount	$ 60,000
Minimum \| Viya (formerly Innovative) \| Innovative Pension Benefit
Purchase price allocation:
Discount rate (as a percent)	3.60%
Minimum \| Viya (formerly Innovative) \| Income Approach
Purchase price allocation:
Discounted rate used for fair value of noncontrolling interests	15.00%
Minimum \| Viya (formerly Innovative) \| Customer relationships
Purchase price allocation:
Useful life	7 years
Minimum \| Viya (formerly Innovative) \| Telecommunication Equipment
Purchase price allocation:
Useful life	1 year
Minimum \| Viya (formerly Innovative) \| Telecommunication Equipment \| Income Approach
Purchase price allocation:
Discounted rate used for cash flows	14.00%
Maximum \| Viya (formerly Innovative) \| Innovative Pension Benefit
Purchase price allocation:
Discount rate (as a percent)	3.90%
Maximum \| Viya (formerly Innovative) \| Income Approach
Purchase price allocation:
Discounted rate used for fair value of noncontrolling interests	25.00%
Maximum \| Viya (formerly Innovative) \| Customer relationships
Purchase price allocation:
Useful life	13 years
Maximum \| Viya (formerly Innovative) \| Telecommunication Equipment
Purchase price allocation:
Useful life	18 years
Maximum \| Viya (formerly Innovative) \| Telecommunication Equipment \| Income Approach
Purchase price allocation:
Discounted rate used for cash flows	25.00%