Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data [Abstract]
Net revenues	$ 904,763	$ 813,270	$ 796,759	$ 760,802	$ 851,483	$ 758,994	$ 781,560	$ 750,819	$ 3,275,594	$ 3,142,856	$ 2,918,434
Gross margin	702,010	667,016	664,008	628,196	676,831	623,009	606,304	616,493	2,661,230	2,522,637	2,415,639
Income from operations	112,406	63,798	122,149	51,732	117,408	58,597	54,419	71,887	350,085	302,311	380,717
Net income	$ 131,274	$ 55,925	$ 103,275	$ 28,887	$ 95,228	$ 47,532	$ 53,024	$ 55,939	$ 319,361	$ 251,723	$ 339,523
Basic (USD per share)	$ 0.85	$ 0.35	$ 0.64	$ 0.18	$ 0.59	$ 0.29	$ 0.31	$ 0.30	$ 2.01	$ 1.48	$ 1.82
Diluted (USD per share)	$ 0.84	$ 0.35	$ 0.64	$ 0.18	$ 0.58	$ 0.29	$ 0.31	$ 0.30	$ 1.99	$ 1.47	$ 1.80