Leases - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Operating cash flow from operating leases	$ 1,122
Financing cash flow from finance leases	29	$ 0
ROU assets obtained in exchange for lease obligations, operating leases	24,212
ROU assets obtained in exchange for lease obligations, finance leases	235
Reductions to ROU assets resulting from reductions to lease obligations, operating leases	811
Reductions to ROU assets resulting from reductions to lease obligations, finance leases	$ 26
Weighted average remaining lease term, operating lease	4 years 8 months 12 days
Weighted average remaining lease term, finance lease	2 years 1 month 6 days
Weighted average discount rate, operating lease	4.49%
Weighted average discount rate, finance lease	5.73%