Revenue - Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Trade receivable	$ 11,403	$ 14,261
Unbilled receivable	2,338	5,540
Insurance proceeds receivable (Note 14)	1,978	0
Other short-term receivable	124	9
Allowance for doubtful accounts	(1,216)	(1,411)
Total accounts receivable	$ 14,627	$ 18,399