Retirement Plans (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Retirement Plans
Fair value of plan assets	$ 173.5	$ 209.6
Cash
Retirement Plans
Fair value of plan assets	0.6
Equity mutual funds
Retirement Plans
Fair value of plan assets	23.8	26.1
Target allocation percentage of investments	12.00%
Fixed income mutual funds
Retirement Plans
Fair value of plan assets	168.9	183.5
Target allocation percentage of investments	88.00%
Cash, equity and fixed income mutual funds
Retirement Plans
Fair value of plan assets	193.4
Due to AIP (estimate)
Retirement Plans
Fair value of plan assets	(19.8)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Retirement Plans
Fair value of plan assets	173.5	198.9
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash
Retirement Plans
Fair value of plan assets	0.6
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity mutual funds
Retirement Plans
Fair value of plan assets	23.8	24.6
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income mutual funds
Retirement Plans
Fair value of plan assets	168.9	174.3
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash, equity and fixed income mutual funds
Retirement Plans
Fair value of plan assets	193.4
Quoted Prices in Active Markets for Identical Assets (Level 1) | Due to AIP (estimate)
Retirement Plans
Fair value of plan assets	(19.8)
Significant Observable Inputs (Level 2)
Retirement Plans
Fair value of plan assets		10.7
Significant Observable Inputs (Level 2) | Equity mutual funds
Retirement Plans
Fair value of plan assets		1.5
Significant Observable Inputs (Level 2) | Fixed income mutual funds
Retirement Plans
Fair value of plan assets		$ 9.2