Leases (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	[2]
Operating Leased Assets [Line Items]
Revenue	$ 74,990		$ 74,261	$ 84,262	$ 75,872	$ 71,841		$ 66,116	$ 72,440	$ 69,481	$ 309,385	$ 279,879	$ 270,866
Minimum [Member]
Operating Leased Assets [Line Items]
Lease term											1 year
Maximum [Member]
Operating Leased Assets [Line Items]
Lease term											35 years
Real Estate [Member]
Operating Leased Assets [Line Items]
Revenue											$ 15,208	$ 16,415	$ 13,944

[1] Net income for the 4th quarter of 2017 includes approximately $2.5 million net tax benefit from non-recurring items of tax benefit and expense related to the Tax Cuts and Jobs Act enacted December 2017 and dissolution of a non-operating foreign subsidiary.

[2] Certain prior year balances have been reclassified to conform to the 2017 presentation (see Note 2 - Summary of Significant Accounting Policies - Reclassifications).