Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Stockholders Equity and Earnings Per Common Share Additional Information [Abstract]
Exercise Price Floor on Outstanding Stock Options	$ 11.37
Exercise Price Ceiling on Outstanding Stock Options	$ 26.29
Outstanding Restricted Stock Unit Grant Prices Lower Limit	$ 19.38
Outstanding Restricted Stock Unit Grant Prices Upper Limit	$ 34.73
Outstanding Performance Share Unit Awards Grant Price Range Lower Limit	$ 23.97
Outstanding Performance Share Unit Awards Grant Price Range Upper Limit	$ 33.86
Number of Antidilutive Securities Excluded from Computation of Earnings Per Share		0		200,000
Commission Paid on Common Stock Repurchased	$ 0.1	$ 0.1	$ 0.1	$ 0.1
Authorized Shares of Preferred Stock	25,000,000		25,000,000
Par Value Per Share of Preferred Stock	$ 0.10		$ 0.10
Issued Shares of Preferred Stock	0		0