BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Foreign Currencies (Details)	Dec. 31, 2017
Foreign Currency Fair Value Hedge Derivative [Line Items]
Percentage of investments in foreign platforms	49.00%
Minimum [Member]
Foreign Currency Fair Value Hedge Derivative [Line Items]
Percentage of hedged investment in KWE	50.00%
Maximum [Member]
Foreign Currency Fair Value Hedge Derivative [Line Items]
Percentage of hedged investment in KWE	100.00%