CASH AND RESTRICTED CASH (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 105,102	$ 368,550
Restricted cash and cash equivalents	56	4,091
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	105,158	372,641	$ 95,220	$ 213,516
Other
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents	56	57
Lending Tree Loans | Discover Bank | Cash in escrow from sale of LendingTree Loans
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents	$ 0	$ 4,034