Income Taxes - Deferred Income Tax Assets and Liabilities Recorded on Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Postretirement benefits other than pensions	$ 221		$ 300
Accrued employee benefits	20,834		31,089
Operating loss carryovers	82,017		88,614
Pensions	79,113		37,172
Tax credit carryovers	34,469		35,170
Undistributed earnings of foreign subsidiaries	540		0
Other	21,845		15,447
Gross deferred tax assets	239,039		207,792
Valuation allowance	(30,768)		(33,757)		(49,562)	(36,419)
Deferred tax assets	208,271		174,035
Deferred tax liabilities:
Depreciation	(184,548)		(213,575)
Foreign currency translation adjustments	(4,752)		(3,104)
Undistributed earnings of foreign subsidiaries	0		(71)
Other	(18,420)		(19,747)
Deferred tax liabilities	(207,720)		(236,497)
Net deferred tax assets (liabilities)	551		(62,462)
Current deferred tax assets	1,801		3,912
Current deferred tax liabilities	(6,806)	[1]	(2,853)	[1]
Noncurrent deferred tax assets	62,440		65,667
Noncurrent deferred tax liabilities	(56,884)		(129,188)
Net deferred tax assets (liabilities)	$ 551		$ (62,462)

[1] See Note 19, “Income Taxes.”