Note 2 - Acquisitions - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jun. 14, 2018	Dec. 31, 2020	Dec. 31, 2019
Goodwill		$ 116,777	$ 264,279
Layne Christensen Company [Member]
Cash	$ 2,995
Receivables	70,160
Contract assets	44,947
Inventories	23,424
Other current assets	5,533
Property and equipment	183,030
Investments in affiliates	55,400
Deferred income taxes	20,959
Other noncurrent assets (including $5,906 of restricted cash)	17,868
Total tangible assets	424,316
Identifiable intangible assets	61,548
Identifiable intangible liabilities	6,800
Accounts payable	38,321
Contract liabilities	7,854
Accrued expenses and other current liabilities	47,583
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt	191,500
Other long-term liabilities	31,585
Total liabilities assumed	323,643
Total identifiable net assets acquired	162,221
Goodwill	187,619
Estimated purchase price	$ 349,840