Note 2 - Investments (Detail) - Securities with Unrealized Losses not Recognized in Income (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Less than 12 Months, Fair Value	$ 50,013	$ 47,271
Less than 12 Months, Unrealized Losses	(240)	(163)
12 Months or More, Fair Value	1,253	1,816
12 Months or More, Unrealized Losses	(8)	(7)
Fair Value	51,266	49,087
Unrealized Losses	(248)	(170)
US Government Agencies Debt Securities [Member]
Less than 12 Months, Fair Value	5,463	10,135
Less than 12 Months, Unrealized Losses	(6)	(15)
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Losses	0	0
Fair Value	5,463	10,135
Unrealized Losses	(6)	(15)
US States and Political Subdivisions Debt Securities [Member]
Less than 12 Months, Fair Value	39,624	17,141
Less than 12 Months, Unrealized Losses	(210)	(93)
12 Months or More, Fair Value	579	582
12 Months or More, Unrealized Losses	(1)	(2)
Fair Value	40,203	17,723
Unrealized Losses	(211)	(95)
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	0	513
12 Months or More, Unrealized Losses	0	(2)
Fair Value	0	513
Unrealized Losses	0	(2)
Collateralized Mortgage Obligations [Member]
Less than 12 Months, Fair Value	4,926	19,995
Less than 12 Months, Unrealized Losses	(24)	(55)
12 Months or More, Fair Value	674	721
12 Months or More, Unrealized Losses	(7)	(3)
Fair Value	5,600	20,716
Unrealized Losses	$ (31)	$ (58)