Stock Incentive Plans - Share-Based Compensation (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total compensation cost for share-based payments	$ 700	$ 619	$ 2,147	$ 1,898
Weighted average grant-date fair value of equity instruments granted (per share)	$ 1.72	$ 2.21	$ 1.74	$ 1.92
Total grant date fair value of shares vested during the period	$ 70	$ 70	$ 1,954	$ 2,540
Expected annual forfeiture rate			9.00%	9.00%
Unamortized share-based payments			$ 2,092	$ 2,585
Weighted average period (in years) to be recognized as expense			1 year 4 months 24 days	1 year 6 months