Note 4 - Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Options outstanding, shares (in shares)	50	305
Options outstanding, weighted average exercise price (in dollars per share)	$ 39.54	$ 27.94
Options outstanding, weighted average grant date fair value (in dollars per share)	$ 21.72	$ 22.23	$ 12.65
Options outstanding, aggregate intrinsic value	$ 0
Granted, shares (in shares)	1	0
Stock price (in dollars per share)	$ 22.15	$ 0
Granted, weighted average grant date fair value (in dollars per share)	$ 0	$ 0
Exercised, shares (in shares)	0	(220)
Exercised, weighted average exercise price (in dollars per share)	$ 0	$ 27.31
Exercised, weighted average grant date fair value (in dollars per share)	$ 0	$ 17.36
Forfeited or expired, shares (in shares)	0	(35)
Forfeited or expired, weighted average exercise price (in dollars per share)	$ 0	$ 15.36
Forfeited or expired, weighted average grant date fair value (in dollars per share)	$ 0	$ 7.36
Options outstanding, shares (in shares)	51	50
Options outstanding,, weighted average exercise price (in dollars per share)	$ 39.14	$ 39.54
Options exercisable, shares (in shares)	51
Options exercisable, weighted average exercise price (in dollars per share)	$ 39.14
Options exercisable, aggregate intrinsic value	$ 0
Options unvested, shares (in shares)	0