Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (1,479)	$ (1,348)	$ (1,477)	$ (1,395)
Accumulated other comprehensive income (loss), beginning balance	(63,020)	(79,866)	(99,012)
Other comprehensive income (loss) before reclassifications:
Actuarial gain (loss) for retiree liabilities	(40,934)	3,179	18,818
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	(171)	195	(126)
Other comprehensive income (loss), reclassification from AOCI, Pension and Other Postretirement Benefit Plans, plan curtailment, before tax		12,923	(1,997)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	40	(66)	44
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	3,766	8,061	13,632
Negative prior service cost (reclassified to salaries, wages and benefits)		(51)	(103)
Income Tax (Expense) or Benefit	8,997	(7,461)	(11,078)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(131)	129	(82)
Other comprehensive income (loss), net of tax		16,846	19,146
Accumulated other comprehensive income (loss), ending balance	(91,362)	(63,020)	(79,866)
Total comprehensive income (loss)	40,943	35,341	42,634
Pension Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(60,575)	(77,088)	(97,302)
Other comprehensive income (loss) before reclassifications:
Actuarial gain (loss) for retiree liabilities	(41,051)	3,116	18,424
Other comprehensive income (loss), reclassification from AOCI, Pension and Other Postretirement Benefit Plans, plan curtailment, before tax		12,923
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	3,547	7,778	13,472
Income Tax (Expense) or Benefit	9,037	(7,304)	(11,682)
Other comprehensive income (loss), net of tax	(28,467)	16,513	20,214
Accumulated other comprehensive income (loss), ending balance	(89,042)	(60,575)	(77,088)
Post-Retirement Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(1,097)	(1,301)	(315)
Other comprehensive income (loss) before reclassifications:
Actuarial gain (loss) for retiree liabilities	117	63	394
Other comprehensive income (loss), reclassification from AOCI, Pension and Other Postretirement Benefit Plans, plan curtailment, before tax			(1,997)
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	219	283	160
Negative prior service cost (reclassified to salaries, wages and benefits)		(51)	(103)
Income Tax (Expense) or Benefit	(80)	(91)	560
Other comprehensive income (loss), net of tax	256	204	(986)
Accumulated other comprehensive income (loss), ending balance	$ (841)	$ (1,097)	$ (1,301)