Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements $ in Thousands	Mar. 31, 2016 USD ($)
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	$ 135,763
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	135,763
Maturity Overnight [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	33,087
Maturity Overnight [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	33,087
Maturity Less than 30 Days [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	517
Maturity Less than 30 Days [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	517
Maturity 30 to 89 Days [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	0
Maturity 30 to 89 Days [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	0
Maturity 90 Days to One Year [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	1,400
Maturity 90 Days to One Year [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	1,400
Maturity Over One Year to Four Years [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	100,759
Maturity Over One Year to Four Years [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 9 - Securities Sold Under Agreements to Repurchase (Details) - Maturity of Short and Long-Term Repurchase Agreements [Line Items]
Short and long-term purchase agreements	$ 100,759