Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lessee, Lease, Description [Line Items]
Lease, renewal term	5 years
Sublease income	$ (1.8)	$ (1.9)
Minimum obligations	831.2
Tenant improvements	75.0
Tenant improvement allowance reimbursement	9.2	$ 13.8
Operating leases, not yet commenced, value	$ 116.9
Minimum
Lessee, Lease, Description [Line Items]
Lease, remaining lease term	1 year
Operating sublease, term	1 year
Operating leases, not yet commenced, term of contract	5 years
Maximum
Lessee, Lease, Description [Line Items]
Lease, remaining lease term	16 years
Operating sublease, term	4 years
Operating leases, not yet commenced, term of contract	15 years
Corporate Headquarters Lease
Lessee, Lease, Description [Line Items]
Tenant improvement allowance reimbursement	$ (8.5)
Line of Credit | Letter of Credit | Corporate Headquarters Lease
Lessee, Lease, Description [Line Items]
Letter of credit	$ 34.2