SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018 segment	Oct. 01, 2018 USD ($)
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Number of reporting units | segment	1
Market capitalization in excess net asset value | $		$ 739.3
Market capitalization in excess net asset value, percentage		82.00%