Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES [Abstract]
Accrued expenses	$ 253,627	$ 301,390
Accrued amounts due to mobile operators and other content providers	138,356	92,291
Money transfer settlement obligations	328,962	343,613
Derivative liabilities	23,424	22,495
Accrued expenses and other current liabilities	$ 744,369	$ 759,789