Leases - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Lease renewal term	5 years
Lease termination period	1 year
Weighted average remaining lease term	11 years 8 months 12 days	4 years 6 months
Weighted average discount rate	3.47%	4.13%
Consolidated Entity Excluding Consolidated Funds | Barrow Hanley | Disposal Group, Held-for-sale, Not Discontinued Operations
Lessee, Lease, Description [Line Items]
Right of use assets	$ 12.4
Operating lease liabilities	$ 12.7
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	13 years