Note 14 - Share-based Compensation (Details Textual) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Restricted Stock [Member]
Share-based Payment Arrangement, Expense	$ 2.9	$ 2.8
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	$ 6.8
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	4 years 146 days
Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
Restricted Stock [Member] \| Share Based Compensation Award, Tranche Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
Common Class B [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	70,000	262,000
The 2011 Equity Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	323,850
The 2011 Equity Compensation Plan [Member] \| Common Class B [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,400,000

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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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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Number of shares authorized for issuance under share-based payment arrangement.

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