Note 5 - Supplemental Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Allowance for Doubtful Accounts [Table Text Block]

	Years Ended December 31,
	2020			2019			2018
Balance, beginning of year	$	6,404		$	9,546		$	5,428
Provision for expected credit losses, net of recoveries (1)		500			(1,930	)		8,188
Amounts written off and adjustments		(2,900	)		(1,212	)		(4,070	)
Balance, end of year	$	4,004		$	6,404		$	9,546

Schedule of Inventory, Current [Table Text Block]

	December 31,
	2020(1)		2019
Raw materials and supplies	$	21,770	$	27,415
Work-in-process		5,377		5,739
Finished products		8,413		14,937
Construction materials		9,329		9,102
Total	$	44,889	$	57,193

Property, Plant and Equipment [Table Text Block]

	Estimated Useful Lives			December 31,
	(Years)			2020			2019
Land and land improvements				$	7,851		$	6,703
Buildings and improvements	5	—	40		48,190			49,084
Machinery and equipment	4	—	10		139,844			131,956
Furniture and fixtures	3	—	10		31,188			31,860
Autos and trucks	3	—	10		45,768			45,496
Construction in progress					5,557			7,236
					278,398			272,335
Less – Accumulated depreciation					(185,498	)		(177,449	)
Property, plant & equipment, less accumulated depreciation				$	92,900		$	94,886

Schedule of Accrued Liabilities [Table Text Block]

	December 31,
	2020		2019
Vendor and other accrued expenses	$	17,152	$	26,313
Estimated casualty and healthcare liabilities		10,624		10,702
Job costs		13,416		12,041
Accrued compensation		17,112		17,045
Income taxes payable		1,360		1,751
Total	$	59,664	$	67,852