Employee Benefit Plans (Details 12) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets Category:
Fair value of pension plan assets	$ 242.5	$ 244.6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	53.8	54.8
Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	188.7	189.8
Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Cash and Cash Equivalents [Member]
Assets Category:
Fair value of pension plan assets	3.7	3.9
Cash and Cash Equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	3.7	3.9
Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Cash and Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Guaranteed investment contracts [Member]
Assets Category:
Fair value of pension plan assets	0	1.8
Guaranteed investment contracts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Guaranteed investment contracts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	0	1.8
Guaranteed investment contracts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Commingled pools / Collective Trusts [Member] | U.S. equity [Member]
Assets Category:
Fair value of pension plan assets	33.4	33.7
Commingled pools / Collective Trusts [Member] | U.S. equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Commingled pools / Collective Trusts [Member] | U.S. equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	33.4	33.7
Commingled pools / Collective Trusts [Member] | U.S. equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Commingled pools / Collective Trusts [Member] | International equity [Member]
Assets Category:
Fair value of pension plan assets	48.3	53.8
Commingled pools / Collective Trusts [Member] | International equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Commingled pools / Collective Trusts [Member] | International equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	48.3	53.8
Commingled pools / Collective Trusts [Member] | International equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Commingled pools / Collective Trusts [Member] | Fixed income [Member]
Assets Category:
Fair value of pension plan assets	81.9	74.0
Commingled pools / Collective Trusts [Member] | Fixed income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Commingled pools / Collective Trusts [Member] | Fixed income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	81.9	74.0
Commingled pools / Collective Trusts [Member] | Fixed income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Mutual funds [Member] | U.S. equity [Member]
Assets Category:
Fair value of pension plan assets	38.8	38.2
Mutual funds [Member] | U.S. equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	38.8	38.2
Mutual funds [Member] | U.S. equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Mutual funds [Member] | U.S. equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Mutual funds [Member] | International equity [Member]
Assets Category:
Fair value of pension plan assets	4.4	6.5
Mutual funds [Member] | International equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	4.4	6.5
Mutual funds [Member] | International equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Mutual funds [Member] | International equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Mutual funds [Member] | Fixed income [Member]
Assets Category:
Fair value of pension plan assets	6.9	6.2
Mutual funds [Member] | Fixed income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	6.9	6.2
Mutual funds [Member] | Fixed income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Mutual funds [Member] | Fixed income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Balanced pension trust [Member] | U.S. equity [Member]
Assets Category:
Fair value of pension plan assets	2.1	2.1
Balanced pension trust [Member] | U.S. equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Balanced pension trust [Member] | U.S. equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	2.1	2.1
Balanced pension trust [Member] | U.S. equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Balanced pension trust [Member] | International equity [Member]
Assets Category:
Fair value of pension plan assets	6.5	7.4
Balanced pension trust [Member] | International equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Balanced pension trust [Member] | International equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	6.5	7.4
Balanced pension trust [Member] | International equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Balanced pension trust [Member] | Bonds [Member]
Assets Category:
Fair value of pension plan assets	4.4	5.3
Balanced pension trust [Member] | Bonds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Balanced pension trust [Member] | Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	4.4	5.3
Balanced pension trust [Member] | Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | U.S. equity [Member]
Assets Category:
Fair value of pension plan assets	1.1	1.1
Pension fund [Member] | U.S. equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | U.S. equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	1.1	1.1
Pension fund [Member] | U.S. equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | International equity [Member]
Assets Category:
Fair value of pension plan assets	5.5	5.7
Pension fund [Member] | International equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | International equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	5.5	5.7
Pension fund [Member] | International equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | Fixed income [Member]
Assets Category:
Fair value of pension plan assets	4.8	4.1
Pension fund [Member] | Fixed income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | Fixed income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	4.8	4.1
Pension fund [Member] | Fixed income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | Money market instruments [Member]
Assets Category:
Fair value of pension plan assets	0.7	0.8
Pension fund [Member] | Money market instruments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Category:
Fair value of pension plan assets	0	0
Pension fund [Member] | Money market instruments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Category:
Fair value of pension plan assets	0.7	0.8
Pension fund [Member] | Money market instruments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Category:
Fair value of pension plan assets	$ 0	$ 0