Stock-Based Compensation - Stock Options Activity Rollforward (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding options, beginning of year, number of shares	3,373,655
Granted, number of shares	450,633
Exercised, number of shares	(1,166,507)
Forfeited, number of shares	(26,911)
Expired, number of shares	(107,277)
Outstanding options, end of year, number of shares	2,523,593
Outstanding options exercisable, end of year, number of shares	1,789,687
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding options, beginning of year, weighted average exercise price	$ 16.60
Granted, weighted average exercise price	$ 17.37
Exercised, weighted average exercise price	$ 15.42
Forfeited, weighted average exercise price	$ 15.74
Expired, weighted average exercise price	$ 18.70
Outstanding options, end of year, weighted average exercise price	$ 17.20
Outstanding options exercisable, end of year, weighted average exercise price	$ 17.67
Outstanding options, end of year weighted average remaining contractual term	4 years 11 months 23 days
Outstanding options exercisable, end of year, weighted average remaining contractual term	4 years 2 months 16 days