ACCOUNTS RECEIVABLE, NET (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts receivable, net
Accounts receivable, gross	$ 123,479	$ 134,858
Less: allowance for doubtful accounts	(18,456)	(22,675)
Total	105,023	112,183
Bad debt expense	5,514	16,257	$ 2,549
Billed Revenues
Accounts receivable, net
Accounts receivable, gross	67,021	73,532
Unbilled Revenues
Accounts receivable, net
Accounts receivable, gross	$ 56,458	$ 61,326