Summary Of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]
Number of compensation plans	2
Percentage inventory valued under LIFO	78.00%	79.00%
Higher inventory if FIFO applied entirely	$ 96.1	$ 84.7
Increase (decrease) in cost of goods sold due to LIFO accounting method	11.4	3.8	(3.8)
Effect of LIFO inventory liquidation on income	4.2		18.6
LIFO expense related to inflation	15.6		14.8
Warehousing and administrative expenses charged to inventory	33.8	29.8
Pension expense	1.6	2.5	6.3
Outstanding checks	71.4	83.3
Buildings [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life, maximum years	40
Fixtures And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life, minimum years	2
Estimated useful life, maximum years	10
Capitalized Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life, maximum years	10
Customer Rebates [Member]
Summary Of Significant Accounting Policies [Line Items]
Accrued liabilities	55.7	56.1
Supplier Allowances [Member]
Summary Of Significant Accounting Policies [Line Items]
Receivables related to supplier allowances	81.3	80.8
Retiree Medical Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Pre-tax gain for reversal of actuarially-based liabilities		8.8
Pension expense			$ 0.1