Stock Options, Non-Vested Shares and Performance Stock Units - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) Tranche $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted options outstanding	1,430,000	1,715,000	2,991,000
Granted Performance stock units outstanding	188,000	226,000
Non-vested granted shares remaining outstanding	334,000	396,000	477,000
Non-cash compensation expense | $	$ 5,200,000	$ 4,300,000	$ 6,200,000
Weighted Average Exercise Price, Granted | $ / shares	$ 17.02	$ 13.86
Options granted	100,000	100,000
Weighted-average fair value of options granted | $ / shares	$ 6.03	$ 6.90	$ 1.64
Total grant date fair value of options vested | $	$ 600,000	$ 1,100,000	$ 2,400,000
Total intrinsic value of stock options exercised | $	$ 4,300,000	$ 4,500,000	900,000
Closing stock price | $ / shares	$ 17.77
2003 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of stock options, non-vested shares and performance stock units	4,700,000
Non-cash compensation expense | $	$ 300,000
2007 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted options outstanding	3,500,000
Additional outstanding shares available for grant	2,100,000
Shares available for grant as a percentage of the Company's outstanding common stock	6.20%
Options exercise price decreased | $ / shares	$ 1.08
Unrecognized compensation cost | $	$ 0
Performance Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted Performance stock units outstanding	119,000
Non-vested granted shares remaining outstanding	99,000
Non-cash compensation expense | $	$ 1,100,000
Unrecognized compensation cost | $	$ 1,600,000
Weighted average remaining term recorded for options, in years	1 year 8 months 12 days
Percentage of Target Award to be paid	200.00%
Minimum performance threshold forfeited | $	$ 0
Performance stock unit vesting date.	Dec. 31, 2015
Performance stock unit settlement date	Feb. 08, 2016
Issuance of common stock upon settlement of performance units shares	30,000
Performance Stock Units | First Tranche
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, recognition period	18 months
Performance Stock Units | Second Tranche
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, recognition period	2 years
Performance Stock Units | Third Tranche
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, recognition period	3 years
Performance Stock Units | 2007 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted Performance stock units outstanding	100,000
Number of tranches | Tranche	3
Non-Vested Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted Performance stock units outstanding	200,000	200,000
Shares issued	100,000
Weighted average remaining term recorded for options, in years	2 years 3 months 18 days
Non-vested shares, vesting period, years	4 years
Unrecognized compensation cost | $	$ 3,000,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-cash compensation expense | $	700,000	$ 1,000,000	3,800,000
Unrecognized compensation cost | $	$ 800,000
Weighted average remaining term recorded for options, in years	2 years 8 months 12 days
Nonvested Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-cash compensation expense | $	$ 3,400,000	$ 3,300,000	$ 2,400,000