Income Taxes - Components of Deferred Income Tax Balances (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred income tax liabilities:
Plant, equipment and intangibles	$ (90,414)	$ (97,229)
Deferred income tax assets:
Postretirement, pensions, and stock compensation	34,656	27,592
Reserves and accruals	44,809	33,788
Net operating loss and tax credit carryforwards	217,902	88,307
Valuation allowances	(157,317)	(10,165)
Deferred tax assets	140,050us-gaap_DeferredTaxAssetsNet	139,522us-gaap_DeferredTaxAssetsNet
Net deferred income tax asset	$ 49,636us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 42,293us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred tax assets net operating loss and tax credit carryforwards.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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