Accumulated Other Comprehensive (Loss) Income - Summary of Components of Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Foreign currency transaction loss
Foreign currency transaction gain (loss)	$ 474	$ (1,996)
AOCI Attributable to Parent, Net of Tax
Total accumulated other comprehensive (loss) income, beginning of period	(97,739)	(78,960)
Total accumulated other comprehensive (loss) income, end of period	(96,548)	(76,803)
Accumulated other comprehensive (loss) income
AOCI Attributable to Parent, Net of Tax
Total accumulated other comprehensive (loss) income, beginning of period	(97,739)	(78,960)
Gain (Loss) recognized in OCI, Net	335	1,139
Gain (Loss) reclassified from AOCI to income, Net	856	1,018
Total accumulated other comprehensive (loss) income, end of period	(96,548)	(76,803)
Changes in fair market value of hedges
Changes in AOCI, Gross
Gross, beginning of the period	1,316	289
Other Comprehensive Income (Loss), before Reclassifications, before Tax	315	1,157
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(215)	(114)
Gross, ending balance	1,416	1,332
Changes in AOCI, Income tax (benefit)
Income tax (benefit), beginning of period	(298)	(105)
Income tax (benefit), Gain (Loss) recognized in OCI	(71)	(261)
Income tax (benefit), Gain (Loss) reclassified from AOCI to income	49	25
Income tax (benefit), ending of period	(320)	(341)
AOCI Attributable to Parent, Net of Tax
Total accumulated other comprehensive (loss) income, beginning of period	1,018	184
Gain (Loss) recognized in OCI, Net	244	896
Gain (Loss) reclassified from AOCI to income, Net	(166)	(89)
Total accumulated other comprehensive (loss) income, end of period	1,096	991
Changes in unrealized pension cost
Changes in AOCI, Gross
Gross, beginning of the period	(132,454)	(130,096)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1,319	1,424
Gross, ending balance	(131,135)	(128,672)
Changes in AOCI, Income tax (benefit)
Income tax (benefit), beginning of period	35,893	52,837
Income tax (benefit), Gain (Loss) recognized in OCI	0	0
Income tax (benefit), Gain (Loss) reclassified from AOCI to income	(297)	(317)
Income tax (benefit), ending of period	35,596	52,520
AOCI Attributable to Parent, Net of Tax
Total accumulated other comprehensive (loss) income, beginning of period	(96,561)	(77,259)
Gain (Loss) recognized in OCI, Net	0	0
Gain (Loss) reclassified from AOCI to income, Net	1,022	1,107
Total accumulated other comprehensive (loss) income, end of period	(95,539)	(76,152)
Cumulative translation adjustment
Changes in AOCI, Gross
Gross, beginning of the period	(2,291)	(1,985)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	88	238
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0
Gross, ending balance	(2,203)	(1,747)
Changes in AOCI, Income tax (benefit)
Income tax (benefit), beginning of period	95	100
Income tax (benefit), Gain (Loss) recognized in OCI	3	5
Income tax (benefit), Gain (Loss) reclassified from AOCI to income	0	0
Income tax (benefit), ending of period	98	105
AOCI Attributable to Parent, Net of Tax
Total accumulated other comprehensive (loss) income, beginning of period	(2,196)	(1,885)
Gain (Loss) recognized in OCI, Net	91	243
Gain (Loss) reclassified from AOCI to income, Net	0	0
Total accumulated other comprehensive (loss) income, end of period	$ (2,105)	$ (1,642)