Equity (Detail) - Share Repurchase Activity (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Stockholders' Equity Note [Abstract]
Number of shares repurchased (in shares)	4,084,590	[1]	2,699,714	[1]
Cost of repurchased shares (in Dollars per share)	$ 324,042		$ 195,850

[1] The average cost of the repurchased shares was $81.83 and $70.34 for the three months ended March 31, 2015 and 2014, respectively.