Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	May 27, 2020	Apr. 29, 2020	Jun. 13, 2016	Dec. 09, 2011
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 1,087.8	$ 1,127.6
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 1,049.3	$ 1,049.3
3.20% Senior Notes, due June 2023 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.20%	3.20%			3.20%
3.37% Senior Notes, due June 2025 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.37%	3.37%			3.37%
4.5% Senior Notes | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	4.50%		4.50%	4.50%
4.20% Senior Notes, due December 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	4.20%
4.20% Senior Notes, due December 2021 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	4.20%	4.20%				4.20%
3.00% Senior Notes, due May 2030 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.00%			3.00%