Common Stock - Summary of Stock Option Transactions (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Schedule Of Stock Options [Line Items]
Outstanding balance at Dec. 31, 2013, Number of Shares	1,567
Outstanding balance at Dec. 31, 2013, Weighted Avg. Option Price (per share)	$ 15.62
Outstanding balance at Dec. 31, 2013, Weighted Avg. Remaining Contractual Term	2 years
Stock Options [Member]
Schedule Of Stock Options [Line Items]
Outstanding balance at Dec. 31, 2012, Number of Shares	2,087
Outstanding balance, Number of Shares	0
Exercised, Number of Shares	(507)
Cancelled, Number of Shares	(13)
Outstanding balance at Dec. 31, 2013, Number of Shares	1,567
Exercisable at Dec. 31, 2013, Number of Shares	1,567
Available for future grant at Dec. 31, 2013, Number of Shares	2,725
Outstanding balance at Dec. 31, 2012, Weighted Avg. Option Price (per share)	$ 15.05
Granted, Weighted Avg. Option Price	$ 0.00
Exercised, Weighted Avg. Option Price	$ 13.22
Cancelled, Weighted Avg. Option Price	$ 18.87
Outstanding balance at Dec. 31, 2013, Weighted Avg. Option Price (per share)	$ 15.62
Exercisable at Dec. 31, 2013, Weighted Avg. Option Price	$ 15.62
Outstanding balance at Dec. 31, 2013, Weighted Avg. Remaining Contractual Term	2 years
Exercisable at Dec. 31, 2013, Weighted Avg. Remaining Contractual Term	2 years
Outstanding balance at Dec. 31, 2013, Aggregate Intrinsic Value	$ 2.6
Exercisable at Dec. 31, 2013, Aggregate Intrinsic Value	$ 2.6