Leases - Lease Cost (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating lease cost (cost resulting from lease payments)	$ 2,358
Short-term lease cost	10
Variable lease cost (cost excluded from lease payments)	339
Sublease income	(126)
Total lease cost	2,581
Right-of-use assets obtained in exchange for new lease liabilities during the first quarter of 2019 - operating leases	1,295
Operating lease - operating cash flows (fixed payments)	2,316
Operating lease - operating cash flows (liability reduction)	$ 1,808
Weighted average lease term - operating leases	12 years 3 months 18 days
Weighted average discount rate - operating leases	3.62%