Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Statement [Abstract]
Net sales	$ 1,953,974	$ 1,793,318	$ 1,613,746
Cost of sales	1,386,567	1,261,728	1,142,484
Gross profit	567,407	531,590	471,262
Selling and administrative expenses	415,592	404,973	370,017
Goodwill impairment	6,946	1,550	0
Operating income	144,869	125,067	101,245
Interest expense, net	6,469	7,964	6,619
Income before income taxes and equity earnings	138,400	117,103	94,626
Provision for income taxes	56,744	45,319	37,093
Equity earnings in unconsolidated investments	316	209	105
Net income	$ 81,972	$ 71,993	$ 57,638
Earnings per share:
Basic (in dollars per share)	$ 1.75	$ 1.49	$ 1.17
Diluted (in dollars per share)	$ 1.71	$ 1.47	$ 1.15
Weighted average shares outstanding:
Basic (in shares)	46,937	48,158	49,469
Diluted (in shares)	48,058	48,987	50,161
Cash dividends declared per common share (in dollars per share)	$ 0.62	$ 0.55	$ 0.52