Note 15 - Financial Instruments that are Eligible for Offset in the Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Securities sold under agreements to repurchase	$ 400,000	$ 400,000
Securities sold under agreements to repurchase	400,000	400,000
Securities sold under agreements to repurchase	400,000	400,000
Derivatives	18,050	6,496
Derivatives	18,050	6,496
Derivatives	18,050	6,496
Securities sold under agreements to repurchase	(400,000)	(400,000)
Derivatives, Collateral Posted	$ (18,050)	$ (6,496)