Note 11 - Stockholders' Equity - Dividend Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Per share amount (in dollars per share)	$ 0.095	$ 0.085
Quarterly Dividends 1 [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 2 [Member]
Record date	Mar. 22, 2019
Payment date	Apr. 05, 2019
Per share amount (in dollars per share)	$ 0.085
Dividend payment	$ 1,672
Quarterly Dividends 3 [Member]
Record date	May 22, 2019
Payment date	Jun. 05, 2019
Per share amount (in dollars per share)	$ 0.085
Dividend payment	$ 1,672
Quarterly Dividends 4 [Member]
Record date	Aug. 21, 2019
Payment date	Sep. 05, 2019
Per share amount (in dollars per share)	$ 0.085
Dividend payment	$ 1,691
Quarterly Dividends 5 [Member]
Record date	Nov. 20, 2019
Payment date	Dec. 05, 2019
Per share amount (in dollars per share)	$ 0.085
Dividend payment	$ 1,701

Aggregate dividends declared during the period for each share of common stock outstanding.

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