Earnings Per Common Share - Historical Net Income and Weighted Average Number of Shares of Common Stock Outstanding (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Weighted average number of shares of common stock outstanding	23,692	23,483	23,625	23,463
Shares assumed issued (less shares assumed purchased for treasury) for stock-based compensation	245	220	322	205
Outstanding shares for diluted earnings per share calculation	23,937	23,703	23,947	23,668