Leases - Narrative (Details)	3 Months Ended
	Mar. 31, 2019
Lessee, Lease, Description [Line Items]
Termination period of leases	1 year
Weighted-average discount rate used for operating leases (as a percent)	4.39%
Weighted-average discount rate used for finance leases (as a percent)	1.89%
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	14 years
Renewal term of operating leases	7 years
Renewal term of finance leases	5 years