Equity (Detail) - Share Repurchase Activity (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Sep. 30, 2012
Stockholders' Equity Note [Abstract]
Number of shares repurchased	2,699,714	[1]	976,943	[1]
Cost of repurchased shares	$ 195,850	[2]	$ 48,527

[1] The average purchase price for the shares was $70.34 and $49.67 for the three months ended March 31, 2014 and 2013, respectively.

[2] The cost of repurchased shares for 2014 includes payment for share repurchase transactions that occurred in late December 2013 and were settled in early January 2014.