Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Accrued employee benefits and compensation	$ 5,730	$ 4,269
Tax loss and credit carryforwards	17,761	18,604
Reserves and accruals	5,996	4,935
Operating leases	904	0
Other	2,210	1,953
Total deferred tax assets	32,601	29,761
Less deferred tax asset valuation allowance	(14,625)	(16,889)	$ (8,754)	$ (6,388)
Total deferred tax assets, net of valuation allowance	17,976	12,872
Deferred tax liabilities
Depreciation and amortization	4,025	8,335
Postretirement benefit obligations	1,719	3,234
Unremitted earnings	1,624	1,778
Operating leases	908	0
Other	1,803	2,094
Total deferred tax liabilities	10,079	15,441
Net deferred tax asset (liability)	$ 7,897
Net deferred tax asset (liability)		$ (2,569)