CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME [Abstract]
Sales	$ 289,923	$ 207,855	$ 804,104	$ 588,617
Cost of sales	206,414	148,384	572,492	419,454
Gross profit	83,509	59,471	231,612	169,163
Selling, general and administrative expense	58,995	45,035	166,346	129,554
Total operating income	24,514	14,436	65,266	39,609
Other expense (income)	(21)	(4)	(33)	(40)
Interest expense	2,287	760	3,878	2,805
Income before income taxes	22,248	13,680	61,421	36,844
Provision for income taxes	9,156	5,406	2,460	14,617
Net income	13,092	8,274	36,915	22,227
Preferred stock dividend	23	23	68	68
Net income attributable to common shareholders	13,069	8,251	36,847	22,159
Net income	13,092	8,274	36,915	22,227
Loss on long-term investment, net of income taxes	(45)	0	(286)	0
Cumulative translation adjustment	1,480	0	1,363	0
Comprehensive income	$ 14,567	$ 8,274	$ 37,992	$ 22,227
Basic earnings per share (in dollars per share)	$ 0.91	$ 0.58	$ 2.56	$ 1.55
Weighted average common shares outstanding (in shares)	14,411	14,315	14,375	14,307
Diluted earnings per share (in dollars per share)	$ 0.86	$ 0.55	$ 2.43	$ 1.47
Weighted average common and common equivalent shares outstanding (in shares)	15,251	15,155	15,215	15,147