Commitments and Contingencies - Additional Information (Detail)						1 Months Ended		6 Months Ended		12 Months Ended
	Dec. 17, 2017 Defendant	Jun. 16, 2016 USD ($)	Mar. 04, 2016 USD ($)	Jul. 07, 2014 Defendant	Dec. 12, 2013	May 31, 2007 Defendant	Sep. 30, 2003 Party Defendant	Jun. 30, 2020 USD ($) Defendant	Jun. 30, 2018 Defendant	Dec. 31, 2004 Entity	Dec. 31, 2019 USD ($)	Jan. 31, 2018 USD ($) Party	Mar. 30, 2017 Party
Loss Contingencies [Line Items]
Accrued legal matters | $								$ 17,788,000			$ 17,820,000
Number of third party defendants over which defendants asserted third party claims seeking contribution or cost recovery							300
Litigation settlement interest, percent					20.00%
EPA [Member] | Occidental Chemical Corporation [Member]
Loss Contingencies [Line Items]
Number of potentially responsible parties | Party													20
Number of potentially responsible parties that the EPA intends to enter into a final settlement agreement with | Party												15
Remediation cost for identified responsible parties | $												$ 280,600
8 Mile Stretch of Lower Passaic River [Member]
Loss Contingencies [Line Items]
Cost estimate for remediating Lower Passaic River | $			$ 1,380,000,000
Minimum [Member] | CERCLA [Member] | Occidental Chemical Corporation [Member]
Loss Contingencies [Line Items]
Number of defendants under complaint									120
Minimum [Member] | 17 Mile Stretch of Lower Passaic River [Member] | EPA [Member]
Loss Contingencies [Line Items]
Number of entities to which general notice letters issued | Entity										100
Lower Passaic River [Member]
Loss Contingencies [Line Items]
Number of potentially responsible parties | Party							66
Lower Passaic River [Member] | YPF [Member]
Loss Contingencies [Line Items]
Payment of bankruptcy amount | $		$ 130,000,000
Lower Passaic River [Member] | Minimum [Member] | 17 Mile Stretch of Lower Passaic River [Member]
Loss Contingencies [Line Items]
Parties to perform a remedial investigation and feasibility study						70
MTBE [Member] | NJ [Member]
Loss Contingencies [Line Items]
Number of defendants in the MTBE complaint								50
MTBE [Member] | Minimum [Member] | PA [Member]
Loss Contingencies [Line Items]
Number of defendants in the MTBE complaint				50
MTBE [Member] | Minimum [Member] | MARYLAND [Member]
Loss Contingencies [Line Items]
Number of defendants in the MTBE complaint	60