Stock-Based Compensation - Activity for Stock Option (Detail) shares in Thousands	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Option Shares, Outstanding at beginning of period | shares	3,293
Number of Option Shares, Exercised | shares	(197)
Number of Option Shares, Cancelled/expired/forfeited | shares	(200)
Number of Option Shares, Outstanding at end of period | shares	2,896
Number of Option Shares, Exercisable at end of period | shares	2,681
Weighted-Average Exercise Price, Outstanding at beginning of period | $ / shares	$ 12.18
Weighted-Average Exercise Price, Exercised | $ / shares	3.47
Weighted-Average Exercise Price, Cancelled/expired/forfeited | $ / shares	12.34
Weighted-Average Exercise Price, Outstanding at end of period | $ / shares	12.76
Weighted-Average Exercise Price, Exercisable at end of period | $ / shares	$ 12.95
Weighted-Average Remaining Contractual Term, Outstanding at end of period	2 years 4 months 24 days
Weighted-Average Remaining Contractual Term, Exercisable at end of period	2 years 3 months 18 days