Discontinued Operations (Details)		3 Months Ended				9 Months Ended
		Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Dec. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Expense		$ 4,290,000		$ 4,740,000		$ 19,078,000		$ 22,108,000
Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Revenue		4,300,000		4,700,000		19,100,000		22,100,000
Disposal Group, Including Discontinued Operation, Depreciation and Amortization						437,000		437,000
Capital Expenditure, Discontinued Operations						0		72,000
Deferred Income Tax Expense (Benefit)						8,789,000		11,047,000
Disposal Group, Including Discontinued Operation, Revenue		34,271,000	[1]	51,619,000	[2]	152,573,000	[1]	181,976,000	[2]
Disposal Group, Including Discontinued Operation, Costs of Goods Sold		33,763,000	[1]	50,888,000	[2]	149,464,000	[1]	177,463,000	[2]
Disposal Group, Including Discontinued Operation, Operating Expense		$ 1,361,000		1,574,000		4,818,000		4,791,000
Number of Disposal Transactions		3
Disposal Group, Including Discontinued Operation, Operating Income (Loss)		$ (853,000)		(843,000)		(1,709,000)		(278,000)
Disposal Group, Including Discontinued Operation, Other Expense		75,000		80,000		243,000		248,000
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax		(928,000)		(923,000)		(1,952,000)		(526,000)
Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period		(304,000)		(371,000)		(564,000)		(187,000)
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax		(624,000)		(552,000)		(1,388,000)		(339,000)
Disposal Group, Including Discontinued Operation, Assets, Current		21,155,000				21,155,000				$ 52,681,000
Disposal Group, Including Discontinued Operation, Liabilities		18,110,000				18,110,000				48,672,000
Settlement Gain		0		$ 0		130,000		130,000
Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax		7,000,000.0
Minimum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax		5,000,000.0
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred Income Tax Expense (Benefit)						513,000		403,000
Settlement Gain						623,000		$ 3,295,000
PESCO [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group Including Discontinued Operation Property Plant And Equipment Gross		1,203,000				1,203,000				1,242,000
Disposal Group Including Discontinued Operation Accumulated Depreciation		(334,000)				(334,000)				(206,000)
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	[3]	869,000				869,000				1,036,000
Assets Of Disposal Group Including Discontinued Operation Current Excluding Deferred Charges and Other		21,155,000				21,155,000
Disposal Group, Including Discontinued Operation, Other Assets	[3]	6,310,000				6,310,000				6,626,000
Disposal Group, Including Discontinued Operation, Assets, Current		28,334,000				28,334,000				52,681,000
Disposal Group, Including Discontinued Operation, Assets										60,343,000
Disposal Group, Including Discontinued Operation, Other Liabilities		18,110,000				18,110,000				48,672,000
Disposal Group, Including Discontinued Operation, Liabilities		18,110,000				18,110,000				48,672,000
Disposal Group Including Discontinued Operation Net Assets		$ 10,224,000				$ 10,224,000				$ 11,671,000

[1] ⁽¹⁾ Included in operating revenues and cost of sales for the three and nine months ended September 30, 2019, is $4.3 million and $19.1 million respectively, representing amounts which had been previously eliminated in consolidation related to intercompany activity that will continue with the buyers after the disposition of the assets of PESCO.

[2] ⁽²⁾ Included in operating revenues and cost of sales for the three and nine months ended September 30, 2018 is $4.7 million and $22.1 million respectively, representing amounts which had been previously eliminated in consolidation related to intercompany activity that will continue with the buyers after the disposition of the assets of PESCO.

[3] ⁽¹⁾ These balances have been combined within the condensed consolidated balance sheets to arrive at non-current assets held for sale