Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Net revenues	$ 1,226,583	$ 1,159,912	$ 1,134,671	$ 1,086,305	$ 1,010,800	$ 945,144	$ 931,558	$ 902,423	$ 4,607,471	$ 3,789,925	$ 3,582,395
Gross profit	765,112	726,420	705,650	667,614	626,878	578,493	567,520	559,519	2,864,796	2,332,410	2,164,646
Income from operations	346,983	310,747	294,258	258,256	289,104	267,390	253,078	244,991	1,210,244	1,054,563	1,027,918
Net earnings	$ 443,872	$ 190,273	$ 179,556	$ 158,071	$ 182,081	$ 167,079	$ 158,069	$ 151,416	$ 971,772	$ 658,645	$ 696,067
Earnings Per Share [Abstract]
Basic (in dollars per share)	$ 4.33	$ 1.86	$ 1.76	$ 1.55	$ 1.79	$ 1.65	$ 1.56	$ 1.50	$ 9.51	$ 6.50	$ 6.92
Diluted (in dollars per share)	$ 4.27	$ 1.84	$ 1.74	$ 1.53	$ 1.78	$ 1.63	$ 1.54	$ 1.48	$ 9.39	$ 6.43	$ 6.85