Note 11 - Fair Value Measurements - Fair Value Hierarchy for Cash Equivalents, Marketable Securities and Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Contingent consideration	$ 720	$ 720
Financial instrument liability		825
Total liabilities	113,945	87,728
Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction Seller financed debt	85,560	86,183
Financial instrument liability	25,912
Syndicated Term Note [Member]
Financial instrument liability	1,753
Fair Value, Inputs, Level 1 [Member]
Contingent consideration	0	0
Financial instrument liability		0
Total liabilities	0	0
Fair Value, Inputs, Level 1 [Member] | Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction Seller financed debt	0	0
Financial instrument liability	0
Fair Value, Inputs, Level 1 [Member] | Syndicated Term Note [Member]
Financial instrument liability	0
Fair Value, Inputs, Level 2 [Member]
Contingent consideration	0	0
Financial instrument liability		0
Total liabilities	85,560	86,183
Fair Value, Inputs, Level 2 [Member] | Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction Seller financed debt	85,560	86,183
Financial instrument liability	0
Fair Value, Inputs, Level 2 [Member] | Syndicated Term Note [Member]
Financial instrument liability	0
Fair Value, Inputs, Level 3 [Member]
Contingent consideration	720	720
Financial instrument liability		825
Total liabilities	28,385	1,545
Fair Value, Inputs, Level 3 [Member] | Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction Seller financed debt	0	$ 0
Financial instrument liability	25,912
Fair Value, Inputs, Level 3 [Member] | Syndicated Term Note [Member]
Financial instrument liability	$ 1,753