Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Plans	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policies [Line Items]
Number of compensation plans	2
Percentage inventory valued under LIFO	76.00%	77.00%
Higher inventory if FIFO applied entirely	$ 112.4	$ 107.8
Increase (decrease) in cost of goods sold due to LIFO accounting method	4.6	11.7	11.4
Effect of LIFO inventory liquidation on income	0.6	3.3	4.2
LIFO expense related to inflation increase in cost of sales	5.2	15.0	15.6
Percentage inventory valued under FIFO	87.90%
Warehousing and administrative expenses charged to inventory	38.0	33.3
Pension expense	4.5	5.7	1.6
Outstanding checks	60.8	39.4
Minimum [Member] | Fixtures And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	2 years
Maximum [Member] | Fixtures And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	10 years
Maximum [Member] | Building [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	40 years
Maximum [Member] | Capitalized Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	10 years
Supplier Allowances [Member]
Summary Of Significant Accounting Policies [Line Items]
Receivables related to supplier allowances	103.2	96.9
Customer Rebates [Member]
Summary Of Significant Accounting Policies [Line Items]
Accrued liabilities	$ 52.6	$ 56.3