Income Taxes - Deferred Income Tax Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Stock and long-term compensation plans	$ 2,405	$ 2,284
Foreign NOL & other carryforwards	24,240	23,785
US state NOL carryforwards	670	842
Deferred revenue	684	627
Pension liability	1,509	1,078
Lease liability	2,807
Amortization and depreciation	586	770
Accrued expenses and other	562	1,138
Total gross deferred tax assets	33,463	30,524
Less: Valuation allowance	(17,255)	(15,170)
Net deferred tax assets (liabilities)	16,208	15,354
Deferred tax liabilities:
Accruals	740	549
Foreign tax on unremitted foreign earnings	2,058	1,650
Right of use asset	2,124
Intangible assets	8,046	10,215
Deferred tax liabilities	12,968	12,414
Net deferred tax assets	$ 3,240	$ 2,940