Acquisitions - Pro Forma Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from continuing operations [Abstract]
Revenue									$ 7,136,397,000	$ 6,992,118,000	$ 6,820,886,000
Pro forma									7,145,275,000	7,059,856,000
Earnings from continuing operations [Abstract]
As reported	$ 168,122,000	$ 206,006,000	$ 198,085,000	$ 105,705,000	$ 157,975,000	$ 157,305,000	$ 166,456,000	$ 109,409,000	677,918,000	591,145,000	$ 746,663,000
Pro forma									$ 680,824,000	$ 600,603,000
Basic earnings per share from continuing operations [Abstract]
As reported (in dollars per share)	$ 1.16	$ 1.42	$ 1.36	$ 0.73	$ 1.08	$ 1.07	$ 1.10	$ 0.71	$ 4.67	$ 3.94	$ 4.80
Pro forma (in dollars per share)									4.69	4.01
Diluted earnings per share from continuing operations [Abstract]
As reported (in dollars per share)	$ 1.15	$ 1.40	$ 1.35	$ 0.72	$ 1.07	$ 1.05	$ 1.08	$ 0.70	4.61	3.89	$ 4.73
Pro forma (in dollars per share)									$ 4.63	$ 3.95