REVENUE (Tables)

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Activity in Contract Assets and Liabilities

The following table presents the activity in our contract assets and liabilities for the six months ended June 30, 2018 (in thousands):



Contract Assets⁽¹⁾:
Balance as of December 31, 2017	$	274,699
Additions	12,295
Transfers to Receivables	(32,488		)
Balance as of June 30, 2018	$	254,506

Contract Liabilities⁽²⁾:
Balance as of December 31, 2017	$	3,201
Additions	5,949
Transfers to Revenues	(3,030		)
Balance as of June 30, 2018	$	6,120

_________________________

(1) Includes current balances of $35.6 million and $49.6 million reported within Unbilled revenues in the Consolidated Balance Sheets (unaudited) as of June 30, 2018 and December 31, 2017, respectively, and includes non-current balances of $218.9 million and $225.2 million reported within Unbilled revenues, less current portion in the Consolidated Balance Sheets (unaudited) as of June 30, 2018 and December 31, 2017, respectively. The remaining balances of $22.0 million and $14.3 million included within Unbilled revenues in the Consolidated Balance Sheets (unaudited) as of June 30, 2018 and December 31, 2017, respectively, relate to amounts recognized as revenue but are only billable upon the passage of time and are therefore not contract assets.

(2) Comprised entirely of current balances of $6.1 million and $3.2 million reported within Deferred revenue in the Consolidated Balance Sheets (unaudited) as of June 30, 2018 and December 31, 2017, respectively.

Remaining Performance Obligations

These amounts, as of June 30, 2018, represent estimated minimum revenues that we will invoice or transfer from contract liabilities and recognize in future periods (in thousands):



	Estimated Revenues
Six months ended December 31, 2018	$	187,974
2019	214,915
2020	152,159
2021	132,410
2022	58,698
Thereafter	175,606
Total	$	921,762