Stockholders' Equity - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Equity [Abstract]
Cash Dividend on Common Stock	$ 0.55	$ 0.50
Aggregated Dividend Paid	$ 27.9
Common stock Dividend Payable Date	Apr. 14, 2014
Dividend payable date of record	Mar. 28, 2014
Dividend payable date declared	Feb. 28, 2014
Company repurchased, shares		1.3
Repurchase agreement, Total cost		$ 55.7