Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ (83,823)	$ (82,457)	$ (85,803)	$ (84,983)
Other comprehensive income (loss) before reclassifications	2,137	2,095	7,046	7,559
Amounts reclassified from accumulated other comprehensive income	(1,464)	(1,468)	(4,393)	(4,406)
Net current-period other comprehensive income (loss)	673	627	2,653	3,153
Ending Balance	(83,150)	(81,830)	(83,150)	(81,830)
Changes in Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance				87
Other comprehensive income (loss) before reclassifications				(87)
Amounts reclassified from accumulated other comprehensive income				0
Net current-period other comprehensive income (loss)				(87)
Ending Balance		0		0
Pension and Other Postretirement Benefits Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(80,244)	(80,905)	(83,279)	(83,879)
Other comprehensive income (loss) before reclassifications	2,658	2,903	8,622	8,815
Amounts reclassified from accumulated other comprehensive income	(1,464)	(1,468)	(4,393)	(4,406)
Net current-period other comprehensive income (loss)	1,194	1,435	4,229	4,409
Ending Balance	(79,050)	(79,470)	(79,050)	(79,470)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(3,579)	(1,552)	(2,524)	(1,191)
Other comprehensive income (loss) before reclassifications	(521)	(808)	(1,576)	(1,169)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Net current-period other comprehensive income (loss)	(521)	(808)	(1,576)	(1,169)
Ending Balance	$ (4,100)	$ (2,360)	$ (4,100)	$ (2,360)