PREFERRED STOCK - Repurchases of Depository Shares of Mandatory Convertible Preferred Stock (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended								9 Months Ended
	Sep. 30, 2017	Aug. 31, 2017	Jun. 30, 2017	May 31, 2017	Apr. 30, 2017	Mar. 31, 2017	Feb. 28, 2017	Jan. 31, 2017	Sep. 30, 2017
Equity [Abstract]
Number of Depository Shares Repurchased	25,000	120,000	35,000	65,000	75,500	5,006	40,694	100,000	466,200
Amount Paid for Repurchases	$ 1,419	$ 7,278	$ 2,345	$ 4,709	$ 5,511	$ 351	$ 2,668	$ 6,551	$ 30,832
Average Price Paid per Share	$ 56.75	$ 60.65	$ 67.00	$ 72.44	$ 73.00	$ 70.00	$ 65.57	$ 65.51	$ 66.13