Note 15 - Accumulated Other Comprehensive Loss (Details Textual) $ in Thousands, CAD in Billions, AUD in Billions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 CAD	Dec. 31, 2017 AUD	Dec. 31, 2016 USD ($)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	$ 34,700
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (328,213)			$ (362,930)
Translation Adjustment Functional to Reporting Currency, Net of Tax		CAD 0.1	AUD 0.4