Contingencies (Details) - USD ($)		1 Months Ended		2 Months Ended	3 Months Ended		6 Months Ended
	May 03, 2019	Apr. 30, 2020	Feb. 29, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Amount awarded to plaintiff	$ 3,200,000	$ 300,000				$ 3,200,000
Reduction in award				$ 900,000
Reduction in estimated contingent loss					$ 900,000
Amount of final judgment			$ 8,100,000
Accrual for environmental investigation and remediation activities				4,200,000		$ 4,600,000	$ 4,200,000	$ 4,400,000
Loss contingency receivable								$ 1,500,000
Portion of loss contingency proceeds representing restricted cash							1,000,000.0
Minimum
Loss Contingencies [Line Items]
Estimate of additional expenses				0			0
Maximum
Loss Contingencies [Line Items]
Estimate of additional expenses				$ 3,900,000			$ 3,900,000