Note 5 - Goodwill and Other Intangible Assets - Goodwill (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Balance	$ 7,006
Balance	100,899
Gibson Technical Services, Inc. [Member]
Goodwill acquired	12,339
IMMCO, Inc. [Member]
Goodwill acquired	10,577
Full Moon [Member]
Goodwill acquired	826
Front Line Power Construction, LLC [Member]
Goodwill acquired	70,151
Electric Power Segment [Member]
Balance	0
Balance	70,151
Electric Power Segment [Member] | Gibson Technical Services, Inc. [Member]
Goodwill acquired	0
Electric Power Segment [Member] | IMMCO, Inc. [Member]
Goodwill acquired	0
Electric Power Segment [Member] | Full Moon [Member]
Goodwill acquired	0
Electric Power Segment [Member] | Front Line Power Construction, LLC [Member]
Goodwill acquired	70,151
Renewables Segment [Member]
Balance	7,006
Balance	7,006
Renewables Segment [Member] | Gibson Technical Services, Inc. [Member]
Goodwill acquired	0
Renewables Segment [Member] | IMMCO, Inc. [Member]
Goodwill acquired	0
Renewables Segment [Member] | Full Moon [Member]
Goodwill acquired	0
Renewables Segment [Member] | Front Line Power Construction, LLC [Member]
Goodwill acquired	0
Other Segments [Member]
Balance	0
Balance	0
Other Segments [Member] | Gibson Technical Services, Inc. [Member]
Goodwill acquired	0
Other Segments [Member] | IMMCO, Inc. [Member]
Goodwill acquired	0
Other Segments [Member] | Full Moon [Member]
Goodwill acquired	0
Other Segments [Member] | Front Line Power Construction, LLC [Member]
Goodwill acquired	0
Telecommunications Segment [Member]
Balance
Balance	23,742
Telecommunications Segment [Member] | Gibson Technical Services, Inc. [Member]
Goodwill acquired	12,339
Telecommunications Segment [Member] | IMMCO, Inc. [Member]
Goodwill acquired	10,577
Telecommunications Segment [Member] | Full Moon [Member]
Goodwill acquired	826
Telecommunications Segment [Member] | Front Line Power Construction, LLC [Member]
Goodwill acquired	$ 0