Note 9 - Contractual Maturity of the Agreements (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Maturity Overnight [Member] | US Government Agencies Debt Securities [Member]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	$ 95,209	$ 89,512
Maturity Less than 30 Days [Member] | US Government Agencies Debt Securities [Member]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement
Maturity 30 to 90 Days [Member] | US Government Agencies Debt Securities [Member]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement
Maturity Greater than 90 Days [Member] | US Government Agencies Debt Securities [Member]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	7,329	7,326
US Government Agencies Debt Securities [Member]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	102,538	96,838
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	$ 102,500	$ 96,800