Pension and Other Post Retirement Benefits (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension and Other Post Retirement Details (Textual) [Abstract]
Collective Bargaining Agreement Beginning		2012-01
Previous Collective Bargaining Agreement Expiry		2011-08
Multiemployer Plan Contributions		5.00%
Contributions		$ 8.5	$ 8.4	$ 5.2
Defined Benefit Plan, Contributions by Employer		1.4	0	1.5
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of days notice upon which redemptions from real estate funds are available		60 days
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of days notice upon which redemptions from real estate funds are available		45 days
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate accumulated benefit obligation		408.9	385.4
Unrecognized net actuarial loss (gain)	9.9	7.2	6.0	2.7
Prior Service Credit	(1.0)	(1.0)	(1.0)	(1.0)
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	2.2
Pension and Other Post Retirement Details (Textual) [Abstract]
Defined Benefit Plan, Contributions by Employer		2.2	18.3
Other post-retirement benefit plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net actuarial loss (gain)	(0.2)	(0.3)	(0.3)	(0.4)
Prior Service Credit	(0.1)	(0.1)	(0.1)	(0.1)
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	4.5
Pension and Other Post Retirement Details (Textual) [Abstract]
Defined Benefit Plan, Contributions by Employer		$ 4.2	$ 4.4