Note 9 - Securities Sold Under Agreements to Repurchase - Maturity of Short and Long-Term Repurchase Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Maturity Overnight [Member]
Short and long-term purchase agreements	$ 36,007	$ 33,151
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Maturity Less than 30 Days [Member]
Short and long-term purchase agreements	200	1,202
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Maturity 30 to 90 Days [Member]
Short and long-term purchase agreements
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Maturity 90 Days to One Year [Member]
Short and long-term purchase agreements	1,457	716
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Maturity Over One Year to Four Years [Member]
Short and long-term purchase agreements	1,025	100,758
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Short and long-term purchase agreements	38,689	135,827
Maturity Overnight [Member]
Short and long-term purchase agreements	36,007	33,151
Maturity Less than 30 Days [Member]
Short and long-term purchase agreements	200	1,202
Maturity 30 to 90 Days [Member]
Short and long-term purchase agreements
Maturity 90 Days to One Year [Member]
Short and long-term purchase agreements	1,457	716
Maturity Over One Year to Four Years [Member]
Short and long-term purchase agreements	1,025	100,758
Short and long-term purchase agreements	$ 38,689	$ 135,827