Accumulated Other Comprehensive Loss - Net Change and Ending Balances for Various Components of Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 149,834	$ 211,423	$ 205,148
Net Change	22,330	(3,400)	11,154
Stranded tax effect (Note 15)	0
Ending Balance	161,761	149,834	211,423
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(22,973)	(8,393)	(4,426)
Net Change	11,041	(14,580)	(3,967)
Stranded tax effect (Note 15)	0
Ending Balance	(11,932)	(22,973)	(8,393)
Unrecognized Components of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(38,636)	(49,943)	(65,396)
Net Change	10,582	11,307	15,453
Stranded tax effect (Note 15)	(6,142)
Ending Balance	(34,196)	(38,636)	(49,943)
Unrealized Holding Gains on Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	59	692	984
Net Change	573	(633)	(292)
Stranded tax effect (Note 15)	0
Ending Balance	632	59	692
Realized Gains/Losses from Settlement of Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	551	45	85
Net Change	134	506	(40)
Stranded tax effect (Note 15)	54
Ending Balance	739	551	45
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(60,999)	(57,599)	(68,753)
Net Change	22,330	(3,400)	11,154
Stranded tax effect (Note 15)	(6,088)
Ending Balance	$ (44,757)	$ (60,999)	$ (57,599)