Defendant Asbestos and Environmental Liabilities - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Liability for Asbestos and Environmental Claims, Net [Roll Forward]
Balance as at January 1	$ 203,320	$ 219,164	$ 234,020
Less: Insurance balances recoverable	135,808	122,326	133,032
Net balance as at January 1	67,512	96,838	100,988
Total net paid claims	(13,708)	(6,351)	(6,927)
Amounts recorded in other income (expense):
Net change in actuarial estimates	(4,263)	(23,221)	2,800
Amortization of fair value adjustments	13,500	246	(23)
Total other expense (income)	9,237	(22,975)	2,777
Acquired on purchase of subsidiaries	335,789	0	0
Net balance as at December 31	398,830	67,512	96,838
Plus: Insurance balances recoverable	448,855	135,808	122,326
Balance as at December 31	$ 847,685	$ 203,320	$ 219,164