Leases - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset	$ 15,485		$ 0
Operating lease liability	15,358		$ 0
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset	15,500	$ 15,900
Operating lease liability	$ 15,400	$ 15,900