Note 12 - Stockholders' Equity - Dividend Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Per share amount (in dollars per share)	$ 0.110	$ 0.095	$ 0.220	$ 0.190
Quarterly Dividends 1 [Member]
Record date			Mar. 09, 2021
Payment date			Mar. 25, 2021
Per share amount (in dollars per share)			$ 0.110
Dividend payment	$ 2,262		$ 2,262
Quarterly Dividends 2 [Member]
Record date			May 19, 2021
Payment date			Jun. 03, 2021
Per share amount (in dollars per share)			$ 0.110
Dividend payment	$ 2,267		$ 2,267
Quarterly Dividends 3 [Member]
Record date					Mar. 03, 2020
Payment date					Mar. 19, 2020
Per share amount (in dollars per share)					$ 0.095
Dividend payment					$ 1,917
Quarterly Dividends 4 [Member]
Record date					May 20, 2020
Payment date					Jun. 04, 2020
Per share amount (in dollars per share)					$ 0.095
Dividend payment					$ 1,917
Quarterly Dividends 5 [Member]
Record date					Aug. 27, 2020
Payment date					Sep. 10, 2020
Per share amount (in dollars per share)					$ 0.095
Dividend payment					$ 1,925
Quarterly Dividends 6 [Member]
Record date					Aug. 27, 2020
Payment date					Dec. 03, 2020
Per share amount (in dollars per share)					$ 0.095
Dividend payment					$ 1,936