Earnings Per Share - Weighted-Average Number of Shares of Common Stock Used to Calculate Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Weighted-average number of shares of common stock for calculating basic earnings per share	23,985	23,900	23,968	23,881
Effect of potentially dilutive securities from equity-based compensation	107	49	196	50
Weighted-average number of shares of common stock for calculating diluted earnings per share	24,092	23,949	24,164	23,931