Acquisitions - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition, Pro Forma Information [Abstract]
Acquisition related costs (after tax)									$ 14,674
Amount of nonrecurring expense, excluded from current period net earnings in pro forma financials, related to the fair value adjustments to acquisition-date inventory									11,439
Revenue from continuing operations [Abstract]
As reported	$ 1,777,961	$ 1,707,763	$ 1,686,345	$ 1,622,273	$ 1,694,600	$ 1,787,582	$ 1,758,628	$ 1,715,501	6,794,342	$ 6,956,311	$ 7,752,728
Pro forma									7,473,048	8,130,560
Earnings from continuing operations [Abstract]
As reported	$ 161,162	$ 130,084	$ 118,290	$ 99,356	$ 136,574	$ 186,483	$ 155,634	$ 117,190	508,892	595,881	$ 778,140
Pro forma									$ 555,968	$ 627,196
Basic earnings per share from continuing operations [Abstract]
As reported (in dollars per share)	$ 1.04	$ 0.84	$ 0.76	$ 0.64	$ 0.88	$ 1.20	$ 0.98	$ 0.72	$ 3.28	$ 3.78	$ 4.67
Pro forma (in dollars per share)									3.58	3.98
Diluted earnings per share from continuing operations [Abstract]
As reported (in dollars per share)	$ 1.03	$ 0.83	$ 0.76	$ 0.64	$ 0.87	$ 1.19	$ 0.97	$ 0.72	3.25	3.74	$ 4.61
Pro forma (in dollars per share)									$ 3.55	$ 3.94