EQUITY - Repurchase of Shares of Common Stock (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Equity [Abstract]
Number of Shares Repurchased and Canceled	88,376	574,807	100,713	198,728	527,243	685,990	763,896	1,411,961
Amount for Repurchases	$ 11,868	$ 77,390	$ 13,771	$ 23,173	$ 58,846	$ 78,340	$ 103,029	$ 160,359	$ 194,066
Average Price Paid per Share	$ 134.29	$ 134.64	$ 136.74	$ 116.60	$ 111.61	$ 114.20	$ 134.87	$ 113.57