Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Schedule of Accumulated Other Comprehensive Income [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss)	$ (5,821)		$ (5,821)
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(1,356)	$ (1,341)	(1,356)	$ (1,341)	$ (1,341)	$ (1,477)	$ (1,085)	$ (1,395)
Accumulated other comprehensive income (loss), beginning balance	(77,187)	(94,392)	(79,866)	(99,012)
Other comprehensive income (loss) before reclassifications:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	(24)	(397)	186	75
Other comprehensive income (loss), reclassification from AOCI, Pension and Other Postretirement Benefit Plans, plan curtailment, before tax	12,923		12,923
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	9	141	(65)	(21)
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	2,015	3,408	6,032	10,224
Negative prior service cost (reclassified to salaries, wages and benefits)	(13)	(26)	(39)	(78)
Income tax expense	(3,295)	(1,086)	(4,817)	(3,702)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(15)	(256)	121	54
Other comprehensive income, net of tax	5,785	1,899	8,464	6,519
Accumulated other comprehensive income (loss), ending balance	(71,402)	(92,493)	(71,402)	(92,493)
Total comprehensive income (loss)	(27,099)	4,062	(68,158)	28,475
Pension Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss)	(5,821)		(5,821)
Accumulated other comprehensive income (loss), beginning balance	(74,619)	(93,010)	(77,088)	(97,302)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss), reclassification from AOCI, Pension and Other Postretirement Benefit Plans, plan curtailment, before tax	12,923		12,923
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	1,944	3,368	5,819	10,104
Income tax expense	(3,283)	(1,222)	(4,689)	(3,666)
Other comprehensive income, net of tax	5,763	2,146	8,232	6,438
Accumulated other comprehensive income (loss), ending balance	(68,856)	(90,864)	(68,856)	(90,864)
Post-Retirement Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(1,227)	(297)	(1,301)	(315)
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	71	40	213	120
Negative prior service cost (reclassified to salaries, wages and benefits)	(13)	(26)	(39)	(78)
Income tax expense	(21)	(5)	(63)	(15)
Other comprehensive income, net of tax	37	9	111	27
Accumulated other comprehensive income (loss), ending balance	$ (1,190)	$ (288)	$ (1,190)	$ (288)