Quarterly Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,808,950	$ 1,747,403	$ 1,798,094	$ 1,637,671	$ 1,752,530	$ 1,747,775	$ 1,737,371	$ 1,583,210	$ 6,992,118	$ 6,820,886	$ 6,043,224
Gross profit	644,972	646,520	665,236	602,828	649,893	649,193	654,108	575,853	2,559,556	2,529,047	2,227,552
Earnings from continuing operations	$ 157,975	$ 157,305	$ 166,456	$ 109,409	$ 289,645	$ 159,455	$ 142,475	$ 155,088	$ 591,145	$ 746,663	$ 502,128
Earnings from continuing operations (in dollars per basic share)	$ 1.08	$ 1.07	$ 1.10	$ 0.71	$ 1.86	$ 1.02	$ 0.92	$ 1.00	$ 3.94	$ 4.80	$ 3.23
Earnings from continuing operations (in dollars per diluted share)	$ 1.07	$ 1.05	$ 1.08	$ 0.70	$ 1.83	$ 1.01	$ 0.90	$ 0.99	$ 3.89	$ 4.73	$ 3.21
Net earnings	$ 141,569	$ 157,305	$ 139,959	$ 131,434	$ 296,448	$ 178,912	$ 164,058	$ 172,247	$ 570,267	$ 811,665	$ 508,892
Net earnings (in dollars per basic share)	$ 0.97	$ 1.07	$ 0.92	$ 0.85	$ 1.90	$ 1.15	$ 1.05	$ 1.11	$ 3.80	$ 5.21	$ 3.28
Net earnings (in dollars per diluted share)	$ 0.96	$ 1.05	$ 0.91	$ 0.84	$ 1.88	$ 1.14	$ 1.04	$ 1.09	$ 3.75	$ 5.15	$ 3.25