Stock-Based Compensation and Other Employee Benefit Plans (Summary of Activity, Employee Stock Purchase Plan) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Common Stock [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Common shares issued	94,761	436,925
Employee Stock Purchase Plan [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Cash proceeds (in millions)	$ 2.5	$ 6.0
Weighted average per share price	$ 26.60	$ 13.69
Weighted average per share grant date fair value	$ 6.34	$ 5.55