Share-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation [Abstract]
Stock-based compensation expense under share based plans	$ 408	$ 369	$ 1,258	$ 1,181
Proceeds from employee stock plans and stock option exercises	246	$ 656	1,020	$ 1,483
Unrecognized compensation expense	$ 1,900		$ 1,900
Expected weighted-average recognition period for unrecognized compensation expense			1 year 4 months 24 days