UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Sales	$ 252,287	$ 183,087
Cost of sales	180,813	130,660
Gross profit	71,474	52,427
Selling, general and administrative expense	51,569	40,885
Operating income	19,905	11,542
Other income	15	21
Interest expense	(829)	(1,022)
Income before income taxes	19,091	10,541
Provision for income taxes	7,445	4,198
Net income	11,646	6,343
Preferred stock dividend	(23)	(23)
Net income attributable to common shareholders	11,623	6,320
Net income	11,646	6,343
Loss on long-term investments, net of income taxes	(229)	0
Comprehensive income	$ 11,417	$ 6,343
Basic income per share (in dollars per share)	$ 0.81	$ 0.44
Weighted average common shares outstanding (in shares)	14,328	14,279
Diluted income per share (in dollars per share)	$ 0.77	$ 0.42
Weighted average common and common equivalent shares outstanding (in shares)	15,168	15,119