ACCOUNTS RECEIVABLE, NET (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accounts receivable, net
Accounts receivable, gross	$ 111,759	$ 123,479
Less: allowance for doubtful accounts	(11,594)	(18,456)
Total	100,165	105,023
Billed
Accounts receivable, net
Accounts receivable, gross	61,211	67,021
Unbilled Revenues
Accounts receivable, net
Accounts receivable, gross	$ 50,548	$ 56,458