Commitments And Contingencies (Details)	3 Months Ended
	Mar. 31, 2019 USD ($)
Guarantor Obligations [Line Items]
Maximum potential future undiscounted rental payments	$ 15,100,000
Guarantor Obligations, Payments Made	0
Guarantor Obligations, Expected Future Payments	$ 0
Property Lease Guarantee [Member]
Guarantor Obligations [Line Items]
Property leases	27
Property leases, still in operation	1
Primary Lessee [Member]
Guarantor Obligations [Line Items]
Property leases	5