Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended										1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member]	Dec. 31, 2012 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member]	Dec. 31, 2011 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member]	Dec. 31, 2013 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member] Employee [Member]	Dec. 31, 2013 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member] Non Employee [Member] Maximum [Member]	Dec. 31, 2012 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member] Non Employee [Member] Maximum [Member]	Dec. 31, 2011 Stock Incentive Plan 2008 Member And Stock Incentive Plan 2011 [Member] Non Employee [Member] Maximum [Member]	Feb. 28, 2013 Stock Incentive Plan 2011 [Member]	Dec. 31, 2013 Stock Incentive Plan 2011 [Member]	Dec. 31, 2013 Stock Incentive Plan 2011 [Member] Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional common stock available for issuance (in shares)											3,400,000	3,500,000
Increase in Additional common stock available for issuance (in shares)												4,300,000
Common stock available for issuance (in shares)												1,700,000
Stock options issued (in shares)	3,286			3,300,000	3,300,000	2,300,000		100,000	100,000	100,000
Vesting period							3 years						1 year
Aggregate intrinsic value of options exercised	$ 2.7	$ 13.7	$ 1.4
Unrecognized compensation cost related to nonvested stock awards	$ 15.9
Weighted average period over which unrecognized compensation cost is expected to be recognized	1 year 9 months 18 days