Selected Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]
Net Sales	$ 926,254	$ 980,814	$ 949,938	$ 876,501	$ 813,760	$ 858,424	$ 847,596	$ 806,326	$ 3,733,507	$ 3,326,106	$ 3,133,577
Gross Profit	467,564	498,693	482,667	448,478	411,449	443,395	442,721	421,880	1,897,402	1,719,445	1,614,524
Pre-tax Earnings	188,819	212,988	206,782	178,845	157,274	188,643	192,379	175,172	787,434	713,468	674,155
Net Earnings	$ 118,391	$ 133,314	$ 130,514	$ 111,931	$ 99,229	$ 119,350	$ 121,009	$ 109,048	$ 494,150	$ 448,636	$ 420,536
Basic Net Earnings per Share	$ 0.40	$ 0.45	$ 0.44	$ 0.38	$ 0.33	$ 0.40	$ 0.41	$ 0.37	$ 1.67	$ 1.51	$ 1.42