Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (12)	$ (1,484)	$ (12)	$ (1,479)
Accumulated other comprehensive income (loss), beginning balance	(61,866)	(91,362)
Other comprehensive income (loss) before reclassifications:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax		(7)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	0	2
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	972	3,925
Income Tax (Expense) or Benefit	(222)	(939)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	0	(5)
Other comprehensive income (loss), net of tax		2,979
Accumulated other comprehensive income (loss), ending balance	(61,116)	(88,383)
Total comprehensive income (loss)	138,255	25,644
Pension Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(61,152)	(89,042)
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	941	3,882
Income Tax (Expense) or Benefit	(215)	(931)
Other comprehensive income (loss), net of tax	726	2,951
Accumulated other comprehensive income (loss), ending balance	(60,426)	(86,091)
Post-Retirement Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(702)	(841)
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	31	43
Income Tax (Expense) or Benefit	(7)	(10)
Other comprehensive income (loss), net of tax	24	33
Accumulated other comprehensive income (loss), ending balance	$ (678)	$ (808)