Note 5 - Securities - Securities in a Continuous Loss Position (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
US Government Agencies Debt Securities [Member]
Securities in a Continuours Loss Position, Less Than 12 Months, Fair Value	$ 81,878,000	$ 88,255,000
Securities in a Continuours Loss Position, Less Than 12 Months, Unrealized Loss	200,000	1,800,000
Continuous Unrealized Loss Position Twelve Months or Longer Fair Value	3,659,000	84,959,000
Continuous Unrealized Loss Position 12 Months or Longer Aggregate Losses	39,000	3,329,000
US States and Political Subdivisions Debt Securities [Member]
Securities in a Continuours Loss Position, Less Than 12 Months, Fair Value	0	3,449,000
Securities in a Continuours Loss Position, Less Than 12 Months, Unrealized Loss	0	24,000
Continuous Unrealized Loss Position Twelve Months or Longer Fair Value	2,210,000	10,161,000
Continuous Unrealized Loss Position 12 Months or Longer Aggregate Losses	36,000	306,000
Corporate Debt Securities [Member]
Securities in a Continuours Loss Position, Less Than 12 Months, Fair Value	0	4,974,000
Securities in a Continuours Loss Position, Less Than 12 Months, Unrealized Loss	0	292,000
Continuous Unrealized Loss Position Twelve Months or Longer Fair Value	942,000	200,000
Continuous Unrealized Loss Position 12 Months or Longer Aggregate Losses	35,000	1,000
Other Securities [Member]
Securities in a Continuours Loss Position, Less Than 12 Months, Fair Value	0	0
Securities in a Continuours Loss Position, Less Than 12 Months, Unrealized Loss	0	0
Continuous Unrealized Loss Position Twelve Months or Longer Fair Value	141,000	127,000
Continuous Unrealized Loss Position 12 Months or Longer Aggregate Losses	48,000	62,000
Securities in a Continuours Loss Position, Less Than 12 Months, Fair Value	81,878,000	96,678,000
Securities in a Continuours Loss Position, Less Than 12 Months, Unrealized Loss	200,000	2,116,000
Continuous Unrealized Loss Position Twelve Months or Longer Fair Value	6,952,000	95,447,000
Continuous Unrealized Loss Position 12 Months or Longer Aggregate Losses	$ 158,000	$ 3,698,000