RECEIVABLES - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Trade accounts receivable		$ 192,743	$ 207,266
Unbilled revenues		62,864	76,268
Allowance for doubtful accounts		(9,990)	(15,182)	$ (11,308)	$ (7,835)
Total	[1]	$ 245,617	$ 268,352

[1] Includes billed and unbilled amounts, net of allowance for doubtful accounts. See Note 3 for details.