Amount for accounts payable to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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RELATED PARTY TRANSACTIONS (NARRATIVE) (DETAILS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction Line Items
OperatingLeasesFutureMinimumPaymentsDue	$ 174,229
Airmax [Member]
Related Party Transaction Line Items
Purchases from Related Party	1,100	$ 1,000	$ 1,700
Accounts Payable Due from Related Party	375
Conversent [Member]
Related Party Transaction Line Items
Purchases from Related Party	70	100
Netlink [Member]
Related Party Transaction Line Items
Purchases from Related Party		98
CafeX [Member]
Related Party Transaction Line Items
Purchases from Related Party	100	$ 400	$ 250
Motif [Member]
Related Party Transaction Line Items
OperatingLeasesFutureMinimumPaymentsDue	$ 142