Leases Leases - Lease Cost Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Lease, Cost [Abstract]
Operating Lease, Cost	[1]	$ 635	$ 1,107
Financing Cash Flows from Finance Leases		401	358
Operating Cash Flows from Finance Leases		4	17
Lease, Cost		$ 1,040	$ 1,482

[1] (1) Includes short-term leases and variable lease costs, which are immaterial