Accumulated Other Comprehensive Loss - Net Change and Ending Balances for Various Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 149,834
Net Change	$ 4,003	$ 4,488	11,774	$ 1,625
Ending balance	153,995		153,995
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(22,973)	(8,393)
Net Change			10,704	(8,623)
Ending balance	(12,269)	(17,016)	(12,269)	(17,016)
Unrecognized Employee Benefit Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(38,636)	(49,943)
Net Change			688	9,540
Ending balance	(37,948)	(40,403)	(37,948)	(40,403)
Unrealized Holding Gains on Marketable Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			59	692
Net Change			398	314
Ending balance	457	1,006	457	1,006
Realized Losses/Gains from Settlement of Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			551	45
Net Change			(16)	394
Ending balance	535	439	535	439
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(60,999)	(57,599)
Net Change			11,774	1,625
Ending balance	$ (49,225)	$ (55,974)	$ (49,225)	$ (55,974)