Financing Arrangements and Debt - Schedule of Long Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total notes payable	$ 2,809,710	$ 2,828,668
Unamortized debt issuance cost and discount on notes payable	(21,643)	(25,287)
Total notes payable, net of unamortized discount	2,788,067	2,803,381
Senior Unsecured Revolving Credit Facility	200,000	0
Total long-term debt	2,988,067	2,803,381
4.00% notes, due June 2022
Debt Instrument [Line Items]
Total notes payable	259,291	260,251
4.95% notes, due December 2022
Debt Instrument [Line Items]
Total notes payable	317,067	318,417
6.875% notes, due August 2024
Debt Instrument [Line Items]
Total notes payable	542,428	550,000
5.75% notes, due August 2025
Debt Instrument [Line Items]
Total notes payable	548,675	550,000
5.875% notes, due December 2027
Debt Instrument [Line Items]
Total notes payable	543,249	550,000
7.05% notes, due May 2029
Debt Instrument [Line Items]
Total notes payable	250,000	250,000
6.375% notes, due December 2042
Debt Instrument [Line Items]
Total notes payable	$ 349,000	$ 350,000