Income Taxes - Deferred Tax Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Retirement benefits	$ 3,532	$ 5,472
Allowance for doubtful accounts	1,160	1,134
Insurance and litigation reserves	396	497
Postretirement benefits	896	1,056
Supplemental retirement benefits	2,862	2,679
Performance incentives	4,347	3,779
Equity-based compensation	753	1,071
Insurance settlement	4,374	4,581
Operating loss carryforward	8,434	8,602
Foreign tax credit and other credits	1,929	3,043
Uncertain tax positions	(400)	(410)
Other	2,645	2,816
Deferred Tax Assets, Gross, Total	30,928	34,320
Valuation allowance	(7,520)	(7,401)
Total deferred income tax assets, net	23,408	26,919
Depreciation	4,049	4,444
Amortization and other	13,497	15,373
Foreign Pension and Other	1,062	1,295
Unremitted Earnings	7,857	0
Total deferred income tax liabilities	$ 26,465	$ 21,112