Defendant Asbestos and Environmental Liabilities - Liability for Asbestos and Liability Claims (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Estimated future expenses	$ 51,637	$ 19,843
Fair value adjustments	(314,824)	(84,650)
Defendant asbestos and environmental liabilities	847,685	203,320	$ 219,164	$ 234,020
Insurance recoveries related to defendant asbestos and environmental liabilities	549,593	183,676
Fair value adjustments	(100,738)	(47,868)
Insurance balances recoverable	448,855	135,808
Net liabilities relating to defendant asbestos and environmental exposures	398,830	67,512	$ 96,838	$ 100,988
Defendant asbestos liabilities
Loss Contingencies [Line Items]
Defendant asbestos and environmental liabilities	1,100,593	265,975
Defendant environmental liabilities
Loss Contingencies [Line Items]
Defendant asbestos and environmental liabilities	$ 10,279	$ 2,152