Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ 93	$ 2,028
Components of Deferred Tax Assets and Liabilities [Abstract]
Inventories	2,010	1,440
Accrued liabilities	249	413
Stock-based compensation	1,587	2,544
Long-term incentive plan	849	1,600
State net operating loss carryforwards	317	1,509
Foreign net operating loss carryforwards	2,740	1,380
State tax credits	1,514	1,447
Federal benefit related to uncertain tax positions	1,922	2,724
Other	664	1,057
Deferred tax assets, gross	11,852	14,114
Valuation allowance	(3,489)	(1,772)
Total deferred tax assets, net	8,363	12,342
Property, plant, and equipment	(14,910)	(22,173)
Other	(496)	(1,518)
Total deferred tax liabilities	(15,406)	(23,691)
Net deferred tax liabilities	$ (7,043)	$ (11,349)