Note 14 - Acquisition of Klondex Mines Ltd. - Pro Forma Information (Details) - Klondex Mines Ltd [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Sales	$ 156,731	$ 182,489	$ 543,741	$ 573,950
Net (loss) income	(20,735)	(8,877)	4,694	2,523
(Loss) income applicable to common shareholders	$ (20,873)	$ (9,015)	$ 4,280	$ (2,937)
Basic and diluted (loss) income per common share (in dollars per share)	$ (0.04)	$ (0.02)	$ 0.01	$ (0.01)