Commitments and Contingencies - Changes in Accrued Environmental Remediation and Related Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Commitments And Contingent Liabilities [Line Items]
Balance at the beginning of the period	$ 113,636
Additions charged to expense, net	132
Payments, net	(541)
Balance at the end of the period	113,227
Amounts recognized in the Condensed Consolidated Balance Sheet at the end of the period:
Current liability	4,838	4,859
Noncurrent liability	108,389	108,777
Total	$ 113,227