Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Tax credit carryforwards	$ 6,654	$ 11,380
Pension, compensation, and other employee benefits	15,173	22,868
Provisions for losses	5,826	10,235
Net operating loss carryforward	5,195	5,023
State income taxes	2,502	3,790
Other deferred income tax assets	2,796	5,020
Total deferred tax assets	38,146	58,316
Valuation allowance	(4,010)	(3,998)
Foreign deferred tax assets included above	(2,396)	(1,972)
Net deferred tax assets	31,740	52,346
Deferred tax liabilities:
Property and equipment	(10,530)	(3,299)
Deferred tax related to life insurance	(3,556)	(5,642)
Goodwill and other intangible assets	(4,299)	(4,535)
Other deferred income tax liabilities	(463)	(557)
Total deferred tax liabilities	(18,848)	(14,033)
Foreign deferred tax liabilities included above	7,869	2,852
United States net deferred tax assets	$ 20,761	$ 41,165