Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
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		23.97
Outstanding Restricted Stock Unit Grant Prices Upper Limit		36.95
Outstanding Performance Share Unit Awards Grant Price Range Lower Limit		23.97
Outstanding Performance Share Unit Awards Grant Price Range Upper Limit		$ 34.08
Number of Antidilutive Securities Excluded from Computation of Earnings Per Share	100,000	300,000
Commission Paid on Common Stock Repurchased		$ 0.1	$ 0.1
Authorized Shares of Preferred Stock	25,000,000	25,000,000
Par Value Per Share of Preferred Stock	$ 0.1	$ 0.1
Issued Shares of Preferred Stock	0	0