Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Information [Line Items]
Sales	$ 900,647	$ 879,939	$ 755,446	$ 673,750	$ 781,969	$ 729,861	$ 607,921	$ 537,198	$ 3,209,782	$ 2,656,949	$ 1,991,139
Gross Profit	253,800	259,785	216,749	194,963	204,308	206,836	177,604	151,835	925,297	740,583	530,213
Net Income	$ 88,064	$ 94,345	$ 69,823	$ 60,078	$ 63,899	$ 67,637	$ 48,729	$ 47,310	$ 312,310	$ 227,575	$ 147,138
Diluted Net Income per Share	$ 1.24	$ 1.33	$ 0.98	$ 0.85	$ 0.90	$ 0.95	$ 0.68	$ 0.67	$ 4.40	$ 3.20	$ 2.14