Note 10 - Construction Joint Ventures (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Contract Value of Active Construction Joint Venture Projects	$ 2,300,000
Contract with Customer, Liability	160,245		$ 173,286
Revenue from Contract with Customer, Including Assessed Tax	560,068	$ 653,886
Retained Earnings (Accumulated Deficit)	452,583		481,384
Unconsolidated Construction Corporate Joint Venture [Member]
Contract with Customer, Liability	72,400
Consolidated Construction Corporate Joint Venture [Member]
Contract Value of Active Construction Joint Venture Projects	$ 1,000,000
Unconsolidated Construction Corporate Joint Venture [Member]
Number of Active Joint Venture Projects	7
Contract Value of Active Construction Joint Venture Projects	$ 7,900,000
Affirmative Claim Recovery Estimate	96,600		104,300
Back Charge Claims	2,600		2,700
Retained Earnings (Accumulated Deficit)	(14,500)		(14,000)
Minimum [Member] | Unconsolidated Construction Corporate Joint Venture [Member]
Contract with Customer, Liability	$ 3,200
Equity Method Investment, Ownership Percentage	23.00%
Minimum [Member] | Unconsolidated Construction Corporate Joint Venture [Member]
Contract Value of Active Construction Joint Venture Projects	$ 12,300
Maximum [Member] | Unconsolidated Construction Corporate Joint Venture [Member]
Contract with Customer, Liability	$ 34,400
Equity Method Investment, Ownership Percentage	50.00%
Maximum [Member] | Unconsolidated Construction Corporate Joint Venture [Member]
Contract Value of Active Construction Joint Venture Projects	$ 3,800,000
Variable Interest Entity, Primary Beneficiary [Member] | Consolidated Construction Corporate Joint Venture [Member]
Revenue from Contract with Customer, Including Assessed Tax	61,300	104,300
Net Cash Provided by (Used in) Continuing Operations	$ 24,800	$ 7,600
Variable Interest Entity, Primary Beneficiary [Member] | Minimum [Member] | Consolidated Construction Corporate Joint Venture [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	50.00%
Variable Interest Entity, Primary Beneficiary [Member] | Maximum [Member] | Consolidated Construction Corporate Joint Venture [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	70.00%
Consolidated Construction Corporate Joint Venture [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Number of Active Joint Venture Projects	11
Contract Value of Active Construction Joint Venture Projects	$ 1,700,000
Contract with Customer, Liability	181,300
Consolidated Construction Corporate Joint Venture [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Minimum [Member]
Contract Value of Active Construction Joint Venture Projects	6,100
Contract with Customer, Liability	900
Consolidated Construction Corporate Joint Venture [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Maximum [Member]
Contract Value of Active Construction Joint Venture Projects	432,500
Contract with Customer, Liability	85,100
Performance Guarantee [Member] | Unconsolidated Construction Corporate Joint Venture [Member]
Guarantor Obligations, Current Carrying Value	58,200		$ 64,700
Performance Guarantee [Member] | Unconsolidated Construction Corporate Joint Venture [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted	109,400
Performance Guarantee [Member] | Co-venturer [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted	135,800
Unconsolidated Construction Corporate Joint Venture [Member] | Performance Guarantee [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 245,200