CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME [Abstract]
Sales	$ 348,504	$ 290,097
Cost of sales	246,797	200,990
Gross profit	101,707	89,107
Selling, general and administrative expense	79,546	66,403
Operating income	22,161	22,704
Other expense (income), net	(150)	1
Interest expense	3,397	1,627
Income before income taxes	18,914	21,076
Provision for income taxes	7,296	7,844
Net income	11,618	13,232
Preferred stock dividend	23	23
Net income attributable to common shareholders	11,595	13,209
Net income	11,618	13,232
Loss on long-term investment, net of income taxes	(55)	(724)
Cumulative translation adjustment	(1,290)	(316)
Comprehensive income	$ 10,273	$ 12,192
Basic earnings per share (in dollars per share)	$ 0.79	$ 0.92
Weighted average common shares outstanding (in shares)	14,724	14,395
Diluted earnings per share (in dollars per share)	$ 0.75	$ 0.87
Weighted average common shares and common equivalent shares outstanding (in shares)	15,564	15,235