Share Repurchases - Additional Information (Detail) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	1 Months Ended		12 Months Ended				30 Months Ended
	Nov. 30, 2012	Jul. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Share Repurchase Program [Member]	Dec. 31, 2013 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Purchase of common stock	$ 200,000,000	$ 150,000,000
Payments under share repurchase program			$ 93,750,000	$ 75,000,000	$ 50,000,000	$ 93,800,000	$ 218,800,000
Repurchase of shares						1,700	5,400
Repurchase of shares average price per share						$ 54.76	$ 40.37