Other Income, Net of Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Income, Net of Expenses [Abstract]
Interest income	$ 239	$ 157	$ 453	$ 332
Gain (loss) on investments	34	14	(69)	41
Insurance recovery	635	0	635	0
Other	144	90	494	400
Total	$ 1,052	$ 261	$ 1,513	$ 773