Schedule II Valuation Accounts (Details) - Allowance For Doubtful Accounts [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 7,671		$ 1,738		$ 1,196
Net Additions (Reductions) to Expense	[2]	(6,310)	[1]	5,953	[1]	348
(Deductions)/Recoveries	[3]	(968)		(20)		194
Balance at End of Period		393		7,671		1,738
Customer receivable reserve				5,200
Discontinued Operations [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Net Additions (Reductions) to Expense		$ (166)		$ (339)		$ (104)

[1] Includes a $5.2 million reserve against a customer receivable for the year ended December 31, 2019 and subsequent reduction due to cash collection during the year ended December 31, 2020.

[2] Includes bad debt recovery of $166 for the year ended December 31, 2020 and bad debt expense of $339 and $104 for the years ended December 31, 2019 and 2018, respectively, related to discontinued operations of the Rail business.

[3] Primarily consists of write-offs, net of recoveries and other adjustments.