Quarterly Financial Information (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
Quarterly Financial Data [Abstract]
Net revenues	$ 851,483	$ 758,994	$ 781,560	$ 750,819	$ 802,420	$ 712,731	$ 730,384	$ 672,899	$ 3,142,856	$ 2,918,434	$ 2,586,123
Gross margin	676,831	623,009	606,304	616,493	665,712	588,798	603,144	557,985	2,522,637	2,415,639	2,181,986
Income from operations	117,408	58,597	54,419	71,887	160,854	87,367	75,888	56,608	302,311	380,717	390,778
Net income	$ 95,228	$ 47,532	$ 53,024	$ 55,939	$ 138,644	$ 76,730	$ 64,461	$ 59,688	$ 251,723	$ 339,523	$ 352,547
Basic	$ 0.59	$ 0.29	$ 0.31	$ 0.30	$ 0.75	$ 0.41	$ 0.34	$ 0.32	$ 1.48	$ 1.82	$ 1.89
Diluted	$ 0.58	$ 0.29	$ 0.31	$ 0.30	$ 0.74	$ 0.41	$ 0.34	$ 0.32	$ 1.47	$ 1.80	$ 1.86