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
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Weighted average number of shares of common stock outstanding	23,560	23,447
Shares assumed issued (less shares assumed purchased for treasury) for stock-based compensation	259	397
Outstanding shares for diluted earnings per share calculation	23,819	23,844