Note 13 - Common Shares (Details Textual) - USD ($) $ / shares in Thousands, $ in Thousands	12 Months Ended
	Feb. 13, 2020	Feb. 12, 2020	Dec. 31, 2019	Feb. 13, 2019	Dec. 31, 2018		Feb. 14, 2018	Dec. 31, 2017	Mar. 01, 2017
Common Stock, Shares Authorized			250,000,000		250,000,000	[1]
Common Stock, Shares, Outstanding, Ending Balance			10,585,159		10,627,988	[1]
Stock Repurchased and Retired During Period, Shares			101,816
Stock Repurchased and Retired During Period, Value			$ 4,986
Common Stock, No Par Value			$ 0		$ 0	[1]
Stock Buyback Program 2020 [Member] | Subsequent Event [Member]
Stock Repurchase Program, Authorized Amount		$ 40,000
Stock Buyback Program 2019 [Member]
Stock Repurchase Program, Authorized Amount				$ 40,000
Stock Buyback Program 2019 [Member] | Subsequent Event [Member]
Stock Repurchased and Retired During Period, Shares	101,816	101,816
Stock Repurchased and Retired During Period, Value	$ 5,000	$ 5,000
Stock Buyback Program 2018 [Member]
Stock Repurchase Program, Authorized Amount							$ 40,000
Stock Repurchased and Retired During Period, Shares				0
Stock Buyback Program 2017 [Member]
Stock Repurchase Program, Authorized Amount									$ 40,000
Stock Repurchased and Retired During Period, Shares							0

[1] The Company has initially applied ASC 2016-02 (Topic 842) on January 1, 2019 using the modified retrospective method (note 2(v)). Under this method, the comparative information is not restated.