Consolidated Statements of 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
Income Statement [Abstract]
Net sales	$ 528,027	$ 503,584	$ 1,647,156	$ 1,522,896
Cost of sales	376,526	355,678	1,168,687	1,072,141
Gross profit	151,501	147,906	478,469	450,755
Selling and administrative expenses	103,544	106,993	316,357	311,345
Goodwill impairment	6,946	0	6,946	0
Operating income	41,011	40,913	155,166	139,410
Interest expense, net	1,687	1,641	5,364	5,110
Income before income taxes and equity earnings	39,324	39,272	149,802	134,300
Provision for income taxes	17,965	15,126	60,020	52,377
Equity earnings in unconsolidated investments	16	23	187	185
Net income	$ 21,375	$ 24,169	$ 89,969	$ 82,108
Earnings per share:
Basic (in dollars per share)	$ 0.46	$ 0.50	$ 1.91	$ 1.70
Diluted (in dollars per share)	$ 0.45	$ 0.50	$ 1.87	$ 1.67
Weighted average shares outstanding: [Abstract]
Basic (in shares)	46,574	47,987	47,076	48,357
Diluted (in shares)	47,787	48,772	48,205	49,157
Cash dividends declared per common share	$ 0.16	$ 0.14	$ 0.46	$ 0.41