Note 11 - Equity-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 9,600
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 9 months 18 days
Weighted Average [Member]
Share Price	$ 20.55		$ 27.35
Current Stock Awards [Member]
Share-based Payment Arrangement, Expense	$ 7,000	$ 6,800	$ 9,000
Deferred Stock Units [Member]
Share-based Payment Arrangement, Expense	$ 700	1,100	1,100
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	3 months 18 days
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount	$ 400
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense	$ 0	$ 0	$ 0
Share-based Payment Arrangement, Option [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	7 years
Share-based Payment Arrangement, Option [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Price of a single share of a number of saleable stocks of a company.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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