Stock-Based Compensation and Other Employee Benefit Plans (Schedule of Activity, Employee Stock Purchase Plans) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Common Stock [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Common shares issued (in shares)	24,026	43,172
Employee Stock Purchase Plans [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Cash proceeds (in dollars)	$ 0.8	$ 0.6
Employee Stock Purchase Plans [Member] | Common Stock [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Weighted average price per share (in dollars per share)	$ 32.51	$ 14.77
Weighted average per share grant date fair value (in dollars per share)	$ 8.49	$ 4.03