Note 11 - Share-based Awards and Cash-based Awards - Schedule of Outstanding Restricted Stock Units Issued to Eligible Employees (Details) - Restricted Stock Units (RSUs) [Member] - shares	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Awards expected to vest (in shares)	1,614,722	3,355,917	5,765,251	6,107,248
Vesting in 2020 [Member]
Awards expected to vest (in shares)	821,656
Vesting in 2021 [Member]
Awards expected to vest (in shares)	793,066