Acquisitions - Pro Forma Information (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Business Combination, Pro Forma Information [Abstract]
Aggregate revenue of current period acquisitions included in the Company's consolidated revenue									$ 235,772
Acquisition related costs (after tax)									5,256
Amount of nonrecurring expense, excluded from current period net earnings in pro forma financials, related to the fair value adjustments to acquisition-date inventory									11,335
Revenue from continuing operations [Abstract]
As reported	2,013,831	2,097,605	2,038,289	1,954,614	1,890,962	1,999,550	1,819,594	1,659,048	8,104,339	7,369,154	6,109,507
Pro forma									8,520,236	8,154,035
Earnings from continuing operations [Abstract]
As reported	208,224	233,330	205,156	186,409	197,267	207,515	213,259	155,145	833,119	773,186	619,497
Pro forma									$ 875,257	$ 796,646
Basic earnings per share from continuing operations [Abstract]
As reported (in dollars per share)	$ 1.17	$ 1.28	$ 1.12	$ 1.01	$ 1.07	$ 1.12	$ 1.14	$ 0.83	$ 4.59	$ 4.16	$ 3.31
Pro forma (in dollars per share)									$ 4.82	$ 4.29
Diluted earnings per share from continuing operations [Abstract]
As reported (in dollars per share)	$ 1.16	$ 1.27	$ 1.10	$ 1.00	$ 1.05	$ 1.10	$ 1.12	$ 0.82	$ 4.53	$ 4.09	$ 3.27
Pro forma (in dollars per share)									$ 4.76	$ 4.22