Summary of Significant Accounting Policies Summary of Significant Accounting Policies, Cash Flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 615,830	$ 503,372	$ 489,035
Capital expenditures	(235,545)	(214,501)	(193,446)
Acquisitions, net of cash acquired	(194,824)	(76,171)	(72,859)
Proceeds from divestitures and sales of property and equipment	37,309	52,381	51,813
Payment to Acquire Life Insurance Policy, Investing Activities	(14,760)	(7,360)	(9,050)
Proceeds from Life Insurance Policy	4,824	2,592	2,517
Payments for (Proceeds from) Other Investing Activities	(14,525)	175	0
Net Cash Provided by (Used in) Investing Activities	(414,621)	(242,884)	(221,025)
Proceeds from issuance of long-term debt	396,349	1,787,500	1,060,000
Debt issuance costs	0	(12,939)	(5,232)
Scheduled payments of debt	(34,134)	(468,973)	(36,414)
Early Repayment of Senior Debt			(895,634)
Principal payments on capital leases	(39,686)	(51,106)	(33,119)
Proceeds from exercise of stock options	24,517	33,611	17,662
Excess tax benefits from share-based awards	0	0	12,685
Purchase of Company common stock	(277,611)	(199,637)	(227,928)
Payments of dividends	(123,849)	(108,750)	(98,418)
Purchase of noncontrolling interest	0	(4,580)	(1,961)
Bank overdrafts and other	(15,177)	5,959	(1,095)
Net Cash Provided by (Used in) Financing Activities	(329,181)	(136,427)	(209,454)
Effect of foreign currency	(5,045)	5,034	1,857
Net (decrease) increase in cash, cash equivalents, and restricted cash	(133,017)	129,095	60,413
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 207,584	340,601	211,506	$ 151,093
Adjustments for New Accounting Principle, Early Adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		1,032	25,440
Capital expenditures		0	0
Acquisitions, net of cash acquired		(26,183)	(3,713)
Proceeds from divestitures and sales of property and equipment		23,952	10,503
Payment to Acquire Life Insurance Policy, Investing Activities		(7,360)	(9,050)
Proceeds from Life Insurance Policy		2,592	2,517
Payments for (Proceeds from) Other Investing Activities		0	5,150
Net Cash Provided by (Used in) Investing Activities		(6,999)	(4,893)
Proceeds from issuance of long-term debt			0
Debt issuance costs			0
Scheduled payments of debt			0
Early Repayment of Senior Debt			(20,524)
Principal payments on capital leases			0
Proceeds from exercise of stock options			0
Excess tax benefits from share-based awards			0
Purchase of Company common stock			0
Payments of dividends			0
Purchase of noncontrolling interest			0
Bank overdrafts and other			0
Net Cash Provided by (Used in) Financing Activities		0	(20,524)
Effect of foreign currency		9	3
Net (decrease) increase in cash, cash equivalents, and restricted cash		(5,958)	26
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		10,562	16,520	16,494
Previous Accounting Guidance [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		502,340	463,595
Capital expenditures		(214,501)	(193,446)
Acquisitions, net of cash acquired		(49,988)	(69,146)
Proceeds from divestitures and sales of property and equipment		28,429	41,310
Payment to Acquire Life Insurance Policy, Investing Activities		0	0
Proceeds from Life Insurance Policy		0	0
Payments for (Proceeds from) Other Investing Activities		175	(5,150)
Net Cash Provided by (Used in) Investing Activities		(235,885)	(216,132)
Proceeds from issuance of long-term debt			1,060,000
Debt issuance costs			(5,232)
Scheduled payments of debt			(36,414)
Early Repayment of Senior Debt			(875,110)
Principal payments on capital leases			(33,119)
Proceeds from exercise of stock options			17,662
Excess tax benefits from share-based awards			12,685
Purchase of Company common stock			(227,928)
Payments of dividends			(98,418)
Purchase of noncontrolling interest			(1,961)
Bank overdrafts and other			(1,095)
Net Cash Provided by (Used in) Financing Activities		(136,427)	(188,930)
Effect of foreign currency		5,025	1,854
Net (decrease) increase in cash, cash equivalents, and restricted cash		135,053	60,387
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		$ 330,039	$ 194,986	$ 134,599