Selected Balance Sheet Data, Accounts Receivable (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable, Net
Accounts receivable		$ 58,896	$ 61,506
Less allowance for bad debts		(4,865)	(5,128)
Accounts receivable, net	[1]	$ 54,031	$ 56,378

[1] Accounts receivable, net includes an immaterial amount due from affiliates for 2016 and 2015, respectively.