Leases - Finance Leases (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Leases
Finance Leases, net of accumulated amortization	$ 1,200,000		$ 595,000
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment, Net		Property, Plant and Equipment, Net
Finance leases, amortization expense included in operating expenses	$ 237,000	$ 139,000
Obligations under finance leases	$ 0