Note 4 - Revenue From Contracts With Customers - Revenues Disaggregated (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues from external customers	$ 80,186	$ 70,254
Public Utilities [Member]
Revenues from external customers	37,022	39,251
Telecommunications [Member]
Revenues from external customers	26,878	16,095
Renewables [Member]
Revenues from external customers	14,929	14,464
Product and Service, Other [Member]
Revenues from external customers	1,357	444
Time-and-Materials Contract [Member]
Revenues from external customers	15,268	17,349
Fixed-Price Contract [Member]
Revenues from external customers	22,407	24,525
Unit Price Contract [Member]
Revenues from external customers	42,511	28,380
Electric Power Segment [Member]
Revenues from external customers	38,298	39,695
Electric Power Segment [Member] | Public Utilities [Member]
Revenues from external customers	36,808	39,251
Electric Power Segment [Member] | Telecommunications [Member]
Revenues from external customers	133	0
Electric Power Segment [Member] | Renewables [Member]
Revenues from external customers	0	0
Electric Power Segment [Member] | Product and Service, Other [Member]
Revenues from external customers	1,357	444
Electric Power Segment [Member] | Time-and-Materials Contract [Member]
Revenues from external customers	15,268	17,237
Electric Power Segment [Member] | Fixed-Price Contract [Member]
Revenues from external customers	6,187	7,742
Electric Power Segment [Member] | Unit Price Contract [Member]
Revenues from external customers	16,843	14,716
Telecommunications Segment [Member]
Revenues from external customers	26,959	16,095
Telecommunications Segment [Member] | Public Utilities [Member]
Revenues from external customers	214	0
Telecommunications Segment [Member] | Telecommunications [Member]
Revenues from external customers	26,745	16,095
Telecommunications Segment [Member] | Renewables [Member]
Revenues from external customers	0	0
Telecommunications Segment [Member] | Product and Service, Other [Member]
Revenues from external customers	0	0
Telecommunications Segment [Member] | Time-and-Materials Contract [Member]
Revenues from external customers	0	112
Telecommunications Segment [Member] | Fixed-Price Contract [Member]
Revenues from external customers	1,291	2,319
Telecommunications Segment [Member] | Unit Price Contract [Member]
Revenues from external customers	25,668	13,664
Renewables Segment [Member]
Revenues from external customers	14,929	14,464
Renewables Segment [Member] | Public Utilities [Member]
Revenues from external customers	0	0
Renewables Segment [Member] | Telecommunications [Member]
Revenues from external customers	0	0
Renewables Segment [Member] | Renewables [Member]
Revenues from external customers	14,929	14,464
Renewables Segment [Member] | Product and Service, Other [Member]
Revenues from external customers	0	0
Renewables Segment [Member] | Time-and-Materials Contract [Member]
Revenues from external customers	0	0
Renewables Segment [Member] | Fixed-Price Contract [Member]
Revenues from external customers	14,929	14,464
Renewables Segment [Member] | Unit Price Contract [Member]
Revenues from external customers	$ 0	$ 0