Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (1,355)	$ (1,499)		$ (1,355)		$ (1,059)
Accumulated other comprehensive income (loss), beginning balance	(82,220)	(82,876)	$ (30,330)	(82,876)	$ (29,818)	(29,818)
Other comprehensive income (loss) before reclassifications:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	224	(453)		(453)		224
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(80)			157
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	1,866		80	3,732	159
Negative prior service cost (reclassified to salaries, wages and benefits)	(136)		(872)	(272)	(1,744)
Hedging gain (reclassified to interest expense)	(41)		(11)	(50)	(22)
Income Tax (Expense) or Benefit	43		4	46	8
Income Tax (Expense) or Benefit	(665)		292	(1,053)	584
Other comprehensive income (loss), net of tax	2		(7)	(4)	(14)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	144		0	(296)	0
Other comprehensive income (loss), net of tax			(511)	1,904	(1,023)
Accumulated other comprehensive income (loss), ending balance	(80,972)	(82,220)	(30,841)	(80,972)	(30,841)	(82,876)
Total comprehensive income (loss)	12,032		8,998	21,797	15,219
Pension Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(80,049)	(81,191)	(31,073)	(81,191)	(31,072)	(31,072)
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	1,793		0	3,586	(1)
Income Tax (Expense) or Benefit	(651)		0	(1,302)	0
Other comprehensive income (loss), net of tax	1,142		0	2,284	(1)
Accumulated other comprehensive income (loss), ending balance	(78,907)	(80,049)	(31,073)	(78,907)	(31,073)	(81,191)
Post-Retirement Plans [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(670)	(630)	741	(630)	1,245	1,245
Amounts reclassified from accumulated other comprehensive income:
Actuarial costs (reclassified to salaries, wages and benefits)	73		80	146	160
Negative prior service cost (reclassified to salaries, wages and benefits)	(136)		(872)	(272)	(1,744)
Income Tax (Expense) or Benefit	23		288	46	576
Other comprehensive income (loss), net of tax	(40)		(504)	(80)	(1,008)
Accumulated other comprehensive income (loss), ending balance	(710)	(670)	237	(710)	237	(630)
Derivative [Member]
Schedule of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(2)	4	2	4	9	9
Amounts reclassified from accumulated other comprehensive income:
Accumulated other comprehensive income (loss), ending balance	0	$ (2)	$ (5)	$ 0	$ (5)	$ 4
Accumulated Other Comprehensive Income (Loss) [Member]
Amounts reclassified from accumulated other comprehensive income:
Total comprehensive income (loss)	$ 1,248