Stock-Based Compensation and Other Employee Benefit Plans (Schedule of Activity, Employee Stock Purchase Plans) (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Common Stock [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Common shares issued (in shares)	49,502	83,680
Employee Stock Purchase Plans [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Cash proceeds (in dollars)	$ 1.6	$ 1.3
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)	$ 33.30	$ 15.95
Weighted average per share grant date fair value (in dollars per share)	$ 8.67	$ 4.36