Summary of Significant Accounting Policies Summary of Significant Accounting Policies, Cash Flow (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		$ 628,755	$ 615,830	$ 503,372
Capital expenditures		(239,957)	(235,545)	(214,501)
Business acquisitions, net of cash acquired		(55,644)	(176,252)	(64,652)
Proceeds from divestitures and sales of property and equipment		77,074	37,309	52,381
Payment to Acquire Life Insurance Policy, Investing Activities		(9,026)	(14,760)	(7,360)
Proceeds from Life Insurance Policy		0	4,824	2,592
Payments for (Proceeds from) Other Investing Activities		415	(14,525)	175
Net Cash Provided by (Used in) Investing Activities		(278,511)	(414,621)	(242,884)
Proceeds from issuance of long-term debt		1,149,263	396,349	1,787,500
Debt issuance costs		(15,539)	0	(12,939)
Scheduled payments of debt		(25,471)	(34,134)	(468,973)
Principal payments on finance leases		(42,627)	(39,686)	(51,106)
Proceeds from exercise of stock options		40,922	24,517	33,611
Purchase of Company common stock		(129,589)	(277,611)	(199,637)
Payments of dividends		(131,402)	(123,849)	(108,750)
Purchase of noncontrolling interest		0	0	(4,580)
Bank overdrafts and other		328	(15,177)	5,959
Net Cash Provided by (Used in) Financing Activities		(319,093)	(329,181)	(136,427)
Effect of foreign currency		3,885	(5,045)	5,034
Net (decrease) increase in cash, cash equivalents, and restricted cash		35,036	(133,017)	129,095
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 207,584	242,620	$ 207,584	$ 340,601	$ 211,506
Impact From Change in Depreciable Lives	$ 4,300	$ 12,100
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Basic Earnings Per Share	$ 0.02	$ 0.07