Note 4 - Trading Account Assets (Details) - Net Realized and Change in Net Unrealized Gains on Trading Account Assets - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net Realized and Change in Net Unrealized Gains on Trading Account Assets [Abstract]
Realized gains (losses), net	$ (23)	$ 138	$ 24	$ 316
Unrealized gains (losses), net due to the change in fair value relative to assets held at end of period	(11)	37	47	30
Total trading account income (loss), net	$ (34)	$ 175	$ 71	$ 346