RESTRICTED CASH - Schedule of Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash shown in the Consolidated Balance Sheets	$ 2,988	$ 8,080
Cash and cash equivalents	56,946	148,374
Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows	59,934	$ 156,454	$ 191,677	$ 172,356
Restricted cash deposited with LKE intermediary
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash shown in the Consolidated Balance Sheets	2,513
Restricted cash held in escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash shown in the Consolidated Balance Sheets	$ 475