Leases - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) renewal_option	Mar. 31, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease, number of renewal options | renewal_option	1
Operating leases, rent expense		$ 1,800
Finance lease, extension term	4 years
Outstanding finance lease	$ 34,161
Outstanding finance lease, due next twelve months	$ 7,100
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, renewal term	1 year
Finance lease, term of contract	2 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, renewal term	20 years
Finance lease, term of contract	5 years