Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	Oct. 27, 2020	Sep. 30, 2020	May 29, 2020	Dec. 31, 2019	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Gain contingency, amount held in escrow			$ 20.0
Operating lease, weighted average remaining lease term		11 years 6 months		11 years 4 months 24 days	11 years 4 months 24 days
Operating lease, weighted average discount rate		4.40%		4.40%
Nikolov V. Livent Corp | Pending Litigation
Lessee, Lease, Description [Line Items]
Settlement amount to be paid		$ 7.4
Net loss contingency		2.5
Settlement accrued liability		7.4
Insurance reimbursement receivable		$ 4.9
Subsequent Event | Nikolov V. Livent Corp | Pending Litigation
Lessee, Lease, Description [Line Items]
Settlement amount to be paid	$ 7.4
Positive Outcome Of Litigation, Reimbursement Of Payment
Lessee, Lease, Description [Line Items]
Gain contingency, amount held in escrow			10.0
Positive Outcome Of Litigation, Termination Penalty Repayment
Lessee, Lease, Description [Line Items]
Gain contingency, amount held in escrow			$ 10.0
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease term		2 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease term		15 years