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Note 2 - Business Combination - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Liabilities
Goodwill		$ 22,985	$ 0
Geneva Pipe Company, Inc [Member]
Assets
Cash and cash equivalents	$ 691
Trade and other receivables	7,089
Inventories	5,673
Prepaid expenses and other	356
Property and equipment	9,096
Operating lease right-of-use assets	21,684
Intangible assets	11,165
Total assets acquired	55,754
Liabilities
Accounts payable	1,395
Accrued liabilities	1,189
Operating lease liabilities	20,454
Deferred income taxes	5,343
Other long-term liabilities	939
Total liabilities assumed	29,320
Goodwill	22,985
Total purchase consideration	$ 49,419