Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders Equity and Earnings Per Common Share Additional Information [Abstract]
Exercise Price Floor on Outstanding Stock Options	$ 20.78
Exercise Price Ceiling on Outstanding Stock Options	26.29
Outstanding Restricted Stock Unit Grant Prices Lower Limit	27.85
Outstanding Restricted Stock Unit Grant Prices Upper Limit	53.94
Outstanding Performance Share Unit Awards Grant Price Range Lower Limit	27.85
Outstanding Performance Share Unit Awards Grant Price Range Upper Limit	$ 49.86
Antidilutive Securities Excluded from Computation of Earnings Per Share		400,000	300,000
Authorized Shares of Preferred Stock	25,000,000
Par Value Per Share of Preferred Stock	$ 0.10
Issued Shares of Preferred Stock	0