Summary of Significant Accounting Policies and Procedures (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Centres States Segment	Dec. 31, 2011 Segment	Dec. 31, 2010
Summary of Significant Accounting Policies and Procedures (Additional Textual) [Abstract]
Number of distribution centers	27
Number of states in which products are distributed	41
Allowance for doubtful accounts days	90 days
Inventory valuation LIFO method	86.00%	86.00%
FIFO cost higher than LIFO valuation	$ 10.5	$ 9.6
Company recorded depreciation expense	2.6	2.7	3.1
Shipping and handling products cost	$ 26.3	$ 26.6	$ 25.3
Percentage of consolidated revenues of company's top ten clients		37.00%
Total sales in percentage	12.00%	11.00%	11.00%
Aggregate number of reporting segment	1	1
Maximum [Member]
Summary of Significant Accounting Policies and Procedures (Textual) [Abstract]
Original maturity of cash equivalents	all highly liquid interest-earning investments with an original maturity of three months or less at the date of purchase
Maximum [Member] | Building And Building Improvements [Member]
Summary of Significant Accounting Policies and Procedures (Textual) [Abstract]
Buildings and improvements lives	25 years
Maximum [Member] | Machinery And Equipment [Member]
Summary of Significant Accounting Policies and Procedures (Textual) [Abstract]
Buildings and improvements lives	10 years
Minimum [Member] | Building And Building Improvements [Member]
Summary of Significant Accounting Policies and Procedures (Textual) [Abstract]
Buildings and improvements lives	3 years
Minimum [Member] | Machinery And Equipment [Member]
Summary of Significant Accounting Policies and Procedures (Textual) [Abstract]
Buildings and improvements lives	3 years