Note 8 - Capital Stock (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				6 Months Ended	8 Months Ended		12 Months Ended												119 Months Ended	150 Months Ended
	Jul. 09, 2025	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Aug. 28, 2025	[1],[2]	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2025	Jun. 30, 2025	Oct. 12, 2022	Dec. 09, 2021	Feb. 08, 2018	Jul. 29, 2015
Stock Repurchased and Retired During Period, Value		$ 7,260			$ 2,778
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.36	$ 0.36	$ 0.36	$ 0.36		$ 0.84		$ 1.44	$ 1.8	$ 2.475	$ 3.9	$ 3.95	$ 4.8	$ 5.35	$ 8.4	$ 8.4	$ 9.6	$ 10.8	$ 6.975		$ 68.73
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.12
Share Repurchase Program [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)																										400,000
Stock Repurchase Program, Additional Shares Authorized (in shares)																							4,300,000	3,372,399	904,564
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)		2,719,137				2,719,137															2,719,137	2,719,137	6,183,601	3,539,861	1,061,315	156,751
Stock Repurchased and Retired During Period, Shares (in shares)		1,113,224				1,113,224			396,241												6,257,826
Stock Repurchased and Retired During Period, Value		$ 7,300				$ 7,300			$ 3,300												$ 84,800
Shares Acquired, Average Cost Per Share (in dollars per share)		$ 6.52				$ 6.52			$ 8.3												$ 13.55

[1] On April 9, 2025, the Company declared a dividend of $0.12 per share to be paid on May 29, 2025. The effect of this dividend is included in the table above but is not reflected in the Company’s financial statements as of March 31, 2025.

[2] On July 9, 2025, the Company declared a dividend of $0.12 per share to be paid on August 28, 2025. The effect of this dividend is included in the table above but is not reflected in the Company’s financial statements as of June 30, 2025.