Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) agreement	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($) agreement
Loss Contingencies [Line Items]
Management fees incurred	$ 454	$ 476	$ 1,473	$ 1,240
Incentive management fee	29	176	$ 210	209
Management agreement renewal additional term			1 year
Management agreement written notice of termination period			90 days
Cost of goods and services sold	10,148	10,269	$ 31,318	27,106
Office Building [Member]
Loss Contingencies [Line Items]
Lease expense	43	39	$ 121	116
Number of new leases entered into during period | agreement					3
Lease expiration					Dec. 31, 2019
Rent expense					$ 154
Minimum [Member]
Loss Contingencies [Line Items]
Management fee percent			3.00%
Management agreement term			1 year
Franchise fee percent			3.30%
Other franchiser programs and service fee percent			2.50%
Franchise agreement term			10 years
Maximum [Member]
Loss Contingencies [Line Items]
Management fee percent			3.50%
Incentive fee percent			5.00%
Management agreement term			3 years
Franchise fee percent			5.50%
Other franchiser programs and service fee percent			6.00%
Franchise agreement term			25 years
Maximum [Member] | Office Building [Member]
Loss Contingencies [Line Items]
Lease expiration					Dec. 31, 2021
Land [Member]
Loss Contingencies [Line Items]
Number of land lease agreements related to properties owned | agreement			0
Lease expense		0		9
Franchise [Member]
Loss Contingencies [Line Items]
Cost of goods and services sold	$ 1,159	$ 1,082	$ 3,676	$ 2,697