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Self-Insurance (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Insurance [Line Items]
Self-insurance reserves - current portion	$ 535.8	$ 530.1
Self-insurance reserves - long-term portion	310.6	262.4
Self-insurance reserves [Member]
Insurance [Line Items]
Self-insurance reserves - current portion	35.4	32.3
Self-insurance reserves - long-term portion	47.0	48.0
Total self-insurance liabilities	$ 82.4	$ 80.3

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