Sales by Product Line (Percentages Of Net Sales By Product Line) (Details)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Revenue from External Customer [Line Items]
Total, percentage of net sales	100.00%		100.00%		100.00%
Fasteners [Member]
Revenue from External Customer [Line Items]
Introduced	1967	[1]
Total, percentage of net sales	40.20%	[1]	42.10%	[1]	44.00%	[1]
Tools [Member]
Revenue from External Customer [Line Items]
Introduced	1993
Total, percentage of net sales	9.30%		9.20%		9.30%
Cutting tools [Member]
Revenue from External Customer [Line Items]
Introduced	1996
Total, percentage of net sales	5.50%		5.40%		5.10%
Hydraulics & pneumatics [Member]
Revenue from External Customer [Line Items]
Introduced	1996
Total, percentage of net sales	7.20%		7.30%		7.60%
Material handling [Member]
Revenue from External Customer [Line Items]
Introduced	1996
Total, percentage of net sales	6.10%		5.70%		6.00%
Janitorial supplies [Member]
Revenue from External Customer [Line Items]
Introduced	1996
Total, percentage of net sales	7.30%		7.00%		6.60%
Electrical supplies [Member]
Revenue from External Customer [Line Items]
Introduced	1997
Total, percentage of net sales	4.70%		4.60%		4.70%
Welding supplies [Member]
Revenue from External Customer [Line Items]
Introduced	1997
Total, percentage of net sales	4.70%		4.50%		4.30%
Safety supplies [Member]
Revenue from External Customer [Line Items]
Introduced	1999	[2]
Total, percentage of net sales	12.80%	[2]	11.20%	[2]	9.30%	[2]
Metals [Member]
Revenue from External Customer [Line Items]
Introduced	2001
Total, percentage of net sales	0.40%		0.50%		0.50%
Direct ship [Member]
Revenue from External Customer [Line Items]
Introduced	2004	[3]
Total, percentage of net sales	1.00%	[3]	1.50%	[3]	1.60%	[3]
Office supplies [Member]
Revenue from External Customer [Line Items]
Introduced	2010
Total, percentage of net sales	0.10%		0.10%		0.10%
Other product line [Member]
Revenue from External Customer [Line Items]
Total, percentage of net sales	0.70%		0.90%		0.90%

[1] Fastener product line represents fasteners and miscellaneous supplies.

[2] The safety supplies product line has expanded, as a percentage of sales, in the last several years due to our FAST Solutions® (industrial vending) program.

[3] Direct ship represents a cross section of products from the eleven product lines. The items included here represent certain items with historically low margins which are shipped directly from our distribution channel to our customers, bypassing our store network.