Subsequent Events Subsequent Events (Details) (Details) (USD $) In Millions, unless otherwise specified	35 Months Ended	12 Months Ended
	Dec. 31, 2016 2014 Expanded Share Repurchase Plan [Member]	Dec. 31, 2013 Share Repurchase Plan [Member]
Subsequent Event [Line Items]
Stock Repurchase Program, Remaining Value of Shares Authorized to be Repurchased		$ 43.0
Stock Repurchase Program, Authorized Amount	$ 300.0	$ 300.0