Commitments and Contingencies - Employee Benefit Plans and Labor Agreements (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) agreement employee	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Deferred compensation vesting period	5 years
Deferred compensation matching contributions | $	$ 2.3	$ 2.3	$ 2.2
Deferred compensation liability, current | $	$ 80.1	64.1
Number of collective bargaining agreements | agreement	31
Number of employees covered under collective bargaining agreement | employee	5,900
Number of collective borrowing agreements expiring in 2020 | agreement	7
Number of collective borrowing agreements expired in 2019 | agreement	3
401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Discretionary match contribution percentage	50.00%
Maximum percentage of eligible employee compensation eligible for discretionary employer match contribution	6.00%
Matching contributions | $	$ 11.7	$ 6.5	$ 6.0