PREFERRED STOCK - Repurchases of Depository Shares of Mandatory Convertible Preferred Stock (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			9 Months Ended
	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Sep. 30, 2018
Equity [Abstract]
Number of Depository Shares Repurchased	50,000	150,000	151,900	351,900
Amount Paid for Repurchases	$ 2.4	$ 7.4	$ 7.4	$ 17.2
Average Price Paid per Share	$ 47.05	$ 49.24	$ 49.05	$ 48.85