Accounts Receivable (Allowance) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 379	$ 108	$ 264	$ 119
Provisions for losses on accounts receivables, net of adjustments	13	109	128	98
Accounts receivable written off, net of recoveries	0	(9)	0	(9)
Balance, end of period	$ 392	$ 208	$ 392	$ 208