Note 10 - Share-based Awards and Cash-based Awards - Schedule of Outstanding Restricted Shares Issued to Non-employee Directors (Details) - Restricted Stock [Member] - shares	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Awards expected to vest by period (in shares)	154,128	123,180	181,832	246,528
Vesting in 2021 [Member]
Awards expected to vest by period (in shares)	138,676
Vesting in 2022 [Member]
Awards expected to vest by period (in shares)	15,452