Share-Based Compensation Share Based Compensation (Summmary of Restricted Stock Unit Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Units Outstanding	2,047,158	1,798,543	1,769,420	1,522,038
Weighted Average Grant Price of Restricted Stock Units	$ 25.08	$ 27.39	$ 25.64	$ 23.19
Restricted Stock Units Granted	1,033,167	790,929	727,300
Weighted Average Grant Price of Restricted Stock Units Granted	$ 21.69	$ 29.06	$ 28.81
Restricted Stock Units Vested	(724,713)	(673,385)	(416,755)
Restricted Stock Units Forfeited	(59,839)	(88,421)	(63,163)
Weighted Average Grant Price of Restricted Stock Units Vested	$ 25.88	$ 24.78	$ 22.26
Weighted Average Grant Price of Restricted Stock Forfeited	$ 26.28	$ 27.17	$ 25.48