Note 15 - Stock-based Compensation - Share-based Award Expense Activity (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share-based compensation expense	$ 4,440	$ 4,251
Share-based Payment Arrangement, Option [Member]
Share-based compensation expense	495	255
Restricted Stock [Member]
Share-based compensation expense	1,517	911
Performance Shares [Member]
Share-based compensation expense	$ 2,428	$ 3,085

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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