Debt Debt, Textuals (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	3.62%	4.72%
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	66.00%	69.00%
Line of Credit Facility, Amount Outstanding	$ 525,000	$ 295,000
Letters of Credit, Maximum Borrowing Capacity	34,000	34,000
Principal payments on capital leases	43,598	42,627	$ 39,686
Repayments of Other Debt	2,000	300
Repayments of Debt	1,200,000	1,400,000
Losses on early extinguishment of debt, net	18,428	16,637	10,131
Pledged Assets Separately Reported, Finance Receivables Pledged as Collateral, at Fair Value	2,000	2,700
Pledged Assets, Other, Not Separately Reported on Statement of Financial Position	1,200	600
Long-term Debt, Fair Value	3,836,715	3,583,241
Debt Issuance Costs, Line of Credit Arrangements, Net	14,500
Repayments of Long-term Debt	34,489	25,471	$ 34,134
Debt Instrument, Increase (Decrease), Net		49,300
Redemption Premium	16,100	11,500
Proceeds from Issuance of Debt	1,600,000	1,100,000
Repayments of Lines of Credit	$ 505,000
Document Period End Date	Dec. 31, 2020
May 2019 [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 200,000
April 2027 [Member]
Debt Instrument [Line Items]
Repayments of Debt	800	46,500
Bank Credit Facility due March 2022 [Member]
Debt Instrument [Line Items]
Repayments of Lines of Credit	450,000
Term Loan December 2022 [Member]
Debt Instrument [Line Items]
Notes Payable to Bank, Noncurrent		633,750
Repayments of Other Debt	32,100
Debt Instrument, Periodic Payment	8,500
January 2022 [Member]
Debt Instrument [Line Items]
Repayments of Debt	425,000
May 2024 [Member]
Debt Instrument [Line Items]
Notes Payable to Bank, Noncurrent	601,250
Line of Credit Facility, Amount Outstanding	525,000	295,000
Repayments of Debt	850,000
Debt Instrument, Periodic Payment	32,500	16,300
Proceeds from Lines of Credit	735,000	295,000
August 2030 [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Debt	850,000
June 2029 [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		750,000
December 2022 [Member]
Debt Instrument [Line Items]
Proceeds from Lines of Credit		55,000
Unsecured Debt [Member] | November 2021 [Member]
Debt Instrument [Line Items]
Senior Notes	150,000	150,000
Unsecured Debt [Member] | April 2027 [Member]
Debt Instrument [Line Items]
Senior Notes	152,710	153,465
Unsecured Debt [Member] | December 2027 [Member]
Debt Instrument [Line Items]
Senior Notes	550,000	550,000
Unsecured Debt [Member] | May 2024 [Member]
Debt Instrument [Line Items]
Senior Notes	0	850,000
Unsecured Debt [Member] | August 2030 [Member]
Debt Instrument [Line Items]
Senior Notes	850,000	0
Unsecured Debt [Member] | June 2029 [Member]
Debt Instrument [Line Items]
Senior Notes	$ 750,000	$ 750,000