Investments and Fair Value Measurements (Additional Disclosures Regarding Fair Value Measurements) (Details) - USD ($)	Dec. 31, 2021	Feb. 18, 2021	Dec. 31, 2020	Feb. 25, 2020	Nov. 15, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt carrying value	$ 3,326,327,000		$ 1,732,622,000
Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Closing trading price per $100 as of the last day of trading for the year	100
Unsecured Debt | 2030 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, face amount	750,000,000			$ 750,000,000
Long term debt carrying value	740,287,000
Unsecured Debt | 2030 Notes | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt fair value	763,418,000
Unsecured Debt | 2027 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, face amount	750,000,000				$ 750,000,000
Long term debt carrying value	744,707,000
Unsecured Debt | 2027 Notes | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt fair value	814,148,000
Unsecured Debt | 2026 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, face amount	750,000,000	$ 750,000,000
Long term debt carrying value	742,872,000
Unsecured Debt | 2026 Notes | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt fair value	$ 730,110,000