Additional Financial Information [Tables]

3 Months Ended

Mar. 31, 2018

Additional Financial Information [Abstract]

Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]

	March 31,				December 31,
Cash and Cash Equivalents and Restricted Cash		2018		2017		2017		2016
Cash and cash equivalents	$	48,872	$	14,884	$	50,498	$	5,788
Restricted cash in Other current assets		8		7		6		7
Restricted cash in Other Assets		345		89		428		140
Cash and cash equivalents and restricted cash	$	49,225	$	14,980	$	50,932	$	5,935

	Three months ended
	March 31,
Consolidated Statements of Cash Flows		2018		2017
Cash paid (received) during the period for:
Interest	$	2,408	$	1,643
Income taxes, net of refunds		(1,089)		(160)