Stock-Based Compensation - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share Based Compensation [Abstract]
Option activity, Outstanding, Beginning balance	2,636,596	2,014,238	1,766,236
Option activity, Exercisable, Beginning balance	1,582,165	1,204,786	1,004,232
Option activity shares, Granted	222,625	654,000	467,500
Option activity, Exercised	(59,638)	(2,914)	(4,498)
Option activity, Forfeited	(192,166)	(28,728)	(215,000)
Option activity outstanding, Ending balance	2,607,417	2,636,596	2,014,238	1,766,236
Option activity, Exercisable, Ending balance	1,967,825	1,582,165	1,204,786	1,004,232
Option activity, Outstanding intrinsic value, Ending balance	$ 2.4	$ 2.1	$ 0.3
Option activity, Exercisable intrinsic value, Ending balance	$ 1.8	$ 1.1	$ 0.1
Option activity, Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 7.42	$ 7.98	$ 9.03
Option activity, Weighted Average Exercise Price, Exercisable, Beginning Balance	8.70	9.66	11.09
Option activity Weighted Average Exercise Price, Granted	6.57	5.63	4.49
Option activity Weighted Average Exercise Price, Exercised	4.76	5.15	3.47
Option activity Weighted Average Exercise Price, Forfeited	7.47	5.85	9.15
Option activity, Weighted Average Exercise Price, Outstanding, Ending Balance	7.41	7.42	7.98	$ 9.03
Option activity Weighted Average Exercise Price, Exercisable, Ending Balance	$ 7.97	$ 8.70	$ 9.66	$ 11.09
Weighted average remaining contractual life	6 years	6 years 9 months 18 days	7 years	7 years 4 months 24 days
Weighted average fair value of option grants	$ 3.55	$ 3.33	$ 2.68