Fair Value Measurements Narrative (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014 Fair Value, Inputs, Level 2 [Member] $250 Million Senior Notes [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 2 [Member] $250 Million Senior Notes [Member]	Sep. 30, 2014 Fair Value, Inputs, Level 2 [Member] $400 Million Senior Notes [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 2 [Member] $400 Million Senior Notes [Member]
Fair Value Measurements [Line Items]
Defined benefit plan, transfers between measurement levels	$ 0	$ 0
Debt instrument fair value			$ 271,900,000	$ 261,300,000	$ 427,000,000	$ 416,000,000