Accounts Receivable (Allowance) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of period	$ 274	$ 238	$ 90	$ 115
Provisions for losses on accounts receivables, net of recoveries	43	165	(141)	42
Accounts receivable written off, net of recoveries	(150)	0	(150)	0
Balance, end of period	$ 81	$ 73	$ 81	$ 73