Note 8 - Earnings Per Share Attributable to Common Stockholders - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities (in shares)	2,321	1,335	2,357	1,492
Service Period Stock Options [Member]
Antidilutive Securities (in shares)	1,275	1,111	1,298	1,254
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities (in shares)	160	199	173	213
Performance Stock Options [Member]
Antidilutive Securities (in shares)	886	25	886	25