Stockholders' Equity - Scheduled Vesting for Outstanding Restricted Stock Units (Detail) (Restricted Stock Units) In Millions, unless otherwise specified	Dec. 31, 2013
Restricted Stock Units
Schedule of Vesting [Line Items]
2014	5.4
2015	5.8
2016	3.2
2017	1.6
2018	0.2
Thereafter	0.1
Total	16.3