Note 8 - Share Repurchase Program (Details Textual)		3 Months Ended							12 Months Ended
	Aug. 13, 2020	Dec. 31, 2022 USD ($) shares	Sep. 30, 2022 shares	Jun. 30, 2022 USD ($) shares	Mar. 31, 2022 USD ($) shares	Dec. 31, 2021 shares	Sep. 30, 2021 shares	Mar. 31, 2020 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2020 USD ($)	May 03, 2022 USD ($) shares	Aug. 31, 2020 shares	Aug. 31, 2019 USD ($) shares
Stock Repurchase Program, Authorized Amount | $											$ 50,000,000.0		$ 34,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares) | shares											3,100,000	2,700,000	1,800,000
Stock Repurchased and Retired During Period, Shares (in shares) | shares		0	0	963,000	1,300,000	0	0	53,064
Stock Repurchased and Retired During Period, Value | $				$ 16,800,000	$ 25,000,000.0			$ 597,000	$ 41,753,000	$ 597,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount | $		$ 33,200,000							$ 33,200,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares) | shares		2,200,000							2,200,000
Stock Split To [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	3
Stock Split from [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	2