Note 5 - Securities (Details) - Temporarily Impaired Securities (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Temporarily Impaired Securities:
Less Than 12 Months - Fair Value	$ 228,176	$ 53,709
Less Than 12 Months - Unrealized Loss	19,901	838
12 Months or More - Fair Value	482	615
12 Months or More - Unrealized Loss	135	175
US Government Agencies [Member]
Temporarily Impaired Securities:
Less Than 12 Months - Fair Value	164,695	44,351
Less Than 12 Months - Unrealized Loss	13,032	622
12 Months or More - Fair Value	0	0
12 Months or More - Unrealized Loss	0	0
States and Political Subdivisions [Member]
Temporarily Impaired Securities:
Less Than 12 Months - Fair Value	58,968	9,358
Less Than 12 Months - Unrealized Loss	6,365	216
12 Months or More - Fair Value	309	482
12 Months or More - Unrealized Loss	4	3
Corporate Securities [Member]
Temporarily Impaired Securities:
Less Than 12 Months - Fair Value	4,513
Less Than 12 Months - Unrealized Loss	504
12 Months or More - Fair Value	0
12 Months or More - Unrealized Loss	0
Other Securities [Member]
Temporarily Impaired Securities:
Less Than 12 Months - Fair Value	0	0
Less Than 12 Months - Unrealized Loss	0	0
12 Months or More - Fair Value	173	133
12 Months or More - Unrealized Loss	$ 131	$ 172