Multiemployer (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Amount contributed to defined benefit multiemployear plans	$ 1.3	$ 1.5	$ 1.3
Number of Multiemployer Defined Benefit Pensions Plans	3
Multi-employer Pension Plans, Number of Collective Bargaining Agreements	4
Central States Southeast and Southwest Areas Pension Fund [Member]
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Amount contributed to defined benefit multiemployear plans	0.9	0.9	0.8
Warehouse Employees Local 169 and Employers Joint Pension Fund [Member]
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Amount contributed to defined benefit multiemployear plans	0.1	0.1	0.1
GCIU Employer Retirement Fund [Member]
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Amount contributed to defined benefit multiemployear plans	$ 0.3	$ 0.5	$ 0.4
Maximum [Member] | Red Zone [Member]
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Multi-employer Pension Plans, Percentage of Plan Funded	65.00%
Maximum [Member] | Yellow Zone [Member]
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Multi-employer Pension Plans, Percentage of Plan Funded	80.00%
Minimum [Member] | Green Zone [Member]
Multi Employer Defined Pension Benefit Plans Disclosures [Line Items]
Multi-employer Pension Plans, Percentage of Plan Funded	80.00%