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Summary of Significant Accounting Policies - Narrative - Basis of Presentation and Nature of Operations (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Dec. 19, 2020 $ / shares	Dec. 31, 2020 USD ($) Segment $ / shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 $ / shares	Mar. 10, 2021 $ / shares	Dec. 20, 2020 $ / shares
Short-term Debt [Line Items]
Number of operating segments \| Segment		2
Conversion price per share (in USD per share)						$ 56.00
Cash dividends per share (in USD per share)	$ 5.00	$ 5.00	$ 0	$ 0
Restricted cash \| $		$ 3.0	$ 3.0
Forecast
Short-term Debt [Line Items]
Conversion price per share (in USD per share)					$ 51.00
2¼% Notes
Short-term Debt [Line Items]
Debt instrument interest rate stated percentage	2.25%