Stock-based Compensation - Schedule of Information Regarding Stock Options Outstanding (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, Number of Shares	3,227,167	3,155,631	3,267,838	4,000,526
Options vested and expected to vest using estimated forfeiture rates, Number of Shares	2,994,044	3,019,979	3,151,950
Options exercisable, Number of Shares	1,774,546	2,329,987	2,377,683
Options outstanding, Weighted Average Exercise Price	$ 7.78	$ 6.65	$ 6.61	$ 6.26
Options vested and expected to vest using estimated forfeiture rates, Weighted Average Exercise Price	$ 7.61	$ 6.67	$ 6.62
Options exercisable, Weighted Average Exercise Price	$ 6.67	$ 6.91	$ 6.99
Options outstanding, Weighted Average Remaining Contractual Life (years)	5 years 5 months 16 days	5 years 2 months 27 days	5 years 6 months 11 days
Options vested and expected to vest using estimated forfeiture rates, Weighted Average Remaining Contractual Life (years)	5 years 4 months 28 days	5 years 2 months 1 day	5 years 5 months 9 days
Options exercisable, Weighted Average Remaining Contractual Life (years)	4 years 11 months 12 days	4 years 8 months 9 days	4 years 7 months 10 days
Options outstanding, Aggregate Intrinsic Value	$ 9.9	$ 3.5	$ 1.3
Options vested and expected to vest using estimated forfeiture rates, Aggregate Intrinsic Value	9.6	3.4	1.3
Options exercisable, Aggregate Intrinsic Value	$ 7.5	$ 2.5	$ 0.8