Details of Certain Balance Sheet Accounts (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Receivables, net [Abstract]
Trade accounts	$ 86,177	$ 84,039
Vendor incentives	31,451	29,373
Other, net	1,708	1,761
Total receivables	119,336	115,173
Less allowance for doubtful accounts	(5,477)	(5,900)
Receivables, net	113,859	109,273
Prepaid expenses and other current assets [Abstract]
Prepaid expenses	8,647	7,527
Other current assets	2,633	3,771
Prepaid expenses and other current assets	11,280	11,298
Property and equipment, net [Abstract]
Land	1,641	1,641
Buildings	2,188	2,188
Leasehold improvements	26,254	24,820
Autos and trucks	14,221	7,099
Machinery and equipment	26,871	24,433
Computer equipment	32,875	31,616
Furniture and fixtures	8,388	7,480
Fixed assets in progress	2,384	2,000
Total property and equipment	114,822	101,277
Less accumulated depreciation	(68,256)	(59,883)
Property and equipment, net	46,566	41,394
Accrued expenses and other current liabilities [Abstract]
Salaries	7,625	6,356
Bonuses	22,549	29,786
Other	18,012	12,998
Accrued expenses and other current liabilities	$ 48,186	$ 49,140