Note 8 - Contract Assets and Liabilities (Details Textual) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Contract With Customer Liability, Revenue Recognized Including Opening Balance	$ 159.9	$ 139.2
Aggregate Affirmative Claim Recovery Estimate Included in Contract Asset and Liability	$ 38.6	$ 38.9	$ 39.0
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Brightline Trains Florida LLC [Member]
Concentration Risk, Percentage	14.60%	13.50%	17.20%
Performance Obligations [Member]
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price	$ 41.1	$ 61.5

Aggregate affirmative claim recovery estimate included in contract asset and liability balances.

No definition available.

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- Definition

The amount of revenue recognized including opening balance of contract with customer liability.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
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- Definition

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130551-203045

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