Stockholders' Equity - Summary of the Company's Stock Options Activity (Detail) - Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Options outstanding, beginning of year (in shares)	1,641,083	3,365,692	6,321,076
Number of options, Granted (in shares)	0	0	0
Number of options, Exercised (in shares)	(525,180)	(1,644,146)	(2,671,058)
Number of options, Expired / terminated (in shares)	(13,158)	(80,463)	(284,326)
Number of options, Options outstanding, end of year (in shares)	1,102,745	1,641,083	3,365,692
Number of options, Options exercisable, end of year (in shares)	1,072,145	1,605,789	3,217,146
Number of options, Options expected to vest, end of year (in shares)	25,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, Options outstanding, beginning of year (in dollars per share)	$ 5.26	$ 6.15	$ 6.05
Weighted average exercise price, Granted (in dollars per share)	0.00	0.00	0.00
Weighted average exercise price, Exercised (in dollars per share)	4.95	6.69	5.75
Weighted average exercise price, Expired / terminated (in dollars per share)	7.27	16.59	7.83
Weighted average exercise price, Options outstanding, end of year (in dollars per share)	5.37	5.26	6.15
Weighted average exercise price, Options exercisable, end of year (in dollars per share)	5.39	$ 5.27	$ 6.22
Weighted average exercise price, Options expected to vest, end of year (in dollars per share)	$ 4.75