Allowance for Doubtful Debts (Tables)

12 Months Ended

Dec. 31, 2016

Allowance For Doubtful Debts Disclosure [Abstract]

Schedule of Credit Losses for Financing Receivables, Current [Table Text Block]

		Charged (credited) to
		Beginning	Bad Debt	Charged to			Ending
		Balance	Expense (Recoveries)	Allowance (1)	Other (2)		Balance
		(in thousands)
Year ended December 31, 2014	$	358	(67)	56	(19)	$	328
Year ended December 31, 2015	$	328	(4)	4	(18)	$	310
Year ended December 31, 2016	$	310	309	11	(19)	$	611
(1) Consists of accounts written off, net of recoveries.
(2) Consists of the effect of currency translation.