Trade Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Receivables [Abstract]
Trade receivables	$ 45,946	$ 42,804
Allowance for doubtful accounts	(99)	(119)
Total trade receivable	45,847	42,685	[1]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, January 1	119	170		$ 918
Charges to bad debt expense	27	311	[2]	289	[2]
Write-offs, net	(47)	(362)		(1,037)
Balance, December 31	$ 99	$ 119		$ 170

[1] See Note 4.

[2] See Note 4.