Note 4 - Debt and Equity Securities (Details) - Securities available for sale by contractual maturity: (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Securities available for sale by contractual maturity: [Abstract]
Due in one year or less	$ 22,496
Due in one year or less	22,496
Due after one year through five years	61,372
Due after one year through five years	63,898
Due after five years through ten years	57,855
Due after five years through ten years	57,612
Due after ten years	120,970
Due after ten years	114,329
Total other securities	262,693
Total other securities	258,335	229,453
Mortgage-backed securities	779,141
Mortgage-backed securities	782,388	720,113
Total securities available for sale	1,041,834	915,947
Total securities available for sale	$ 1,040,723	$ 949,566