Stock-based Compensation - Schedule of Stock Options Outstanding and Exercisable (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Options outstanding, beginning balance	1,536
Shares, Options granted
Shares, Options forfeited and expired	(41)
Shares, Options exercised	(372)
Shares, Options outstanding, ending balance	1,123
Shares, Options vested and expected to vest, ending balance	1,098
Shares, Options exercisable, ending balance	841
Weighted average exercise price, Options outstanding, beginning balance	$ 14.19
Weighted average exercise price, Options granted
Weighted average exercise price, Options forfeited and expired	$ 25.63
Weighted average exercise price, Options exercised	$ 11.49
Weighted average exercise price, Options outstanding, ending balance	$ 14.66
Weighted average exercise price, Options vested and expected to vest, ending balance	$ 14.65
Weighted average exercise price, Options exercisable, ending balance	$ 14.59
Weighted average remaining contractual term (years), Options outstanding	3 years 4 months 17 days
Weighted average remaining contractual term (years), Options vested and expected to vest	3 years 3 months 29 days
Weighted average remaining contractual term (years), Options exercisable	2 years 8 months 23 days
Aggregate intrinsic value, Options outstanding	$ 15,304
Aggregate intrinsic value, Options vested and expected to vest	14,981
Aggregate intrinsic value, Options exercisable	$ 11,531