ACCOUNTS RECEIVABLE, NET (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts receivable, net
Accounts receivable, gross	$ 98,245	$ 123,479
Less: allowance for doubtful accounts	(10,424)	(18,456)
Total	87,821	105,023
Bad debt expense	1,829	5,514	$ 16,257
Billed
Accounts receivable, net
Accounts receivable, gross	58,392	67,021
Unbilled
Accounts receivable, net
Accounts receivable, gross	$ 39,853	$ 56,458