Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Mar. 10, 2015	Mar. 31, 2015 Operable_Unit	Dec. 31, 2014
Commitments And Contingencies [Line Items]
Letters of credit contingently liable		$ 456,000	$ 473,000
Number of operable units		2
Damages sought, value	18,000,000
Total environmental accruals		16,499,000	16,859,000
Environmental accrual, long-term portion		7,195,000	7,384,000
Pennsauken Site (OU-1 and OU-2) [Member]
Commitments And Contingencies [Line Items]
Payment for past cost as per agreement installment amount		2,141,000
Payment for past cost as per agreement aggregate amount		10,705,000
Number of equal payments		5
Payment related to obligation		4,396,000
Description of payment period		The third payment is scheduled to be made on June 1, 2015. The fourth and fifth payments will be made on the anniversary of the prior year's payment plus ten days
Financial Assurance [Member]
Commitments And Contingencies [Line Items]
Letters of credit contingently liable		$ 6,423,000	$ 6,423,000
SurfTech [Member]
Commitments And Contingencies [Line Items]
Number of sites		3
Number of sites owned by the Company		2