Note 7 - Investment Securities (Detail) - Investment Securities With Unrealized Losses Not Recognized In Income (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
More 12 Months Unrealized Losses	$ 646
US Government-sponsored Enterprises Debt Securities [Member]
Less 12 Months Fair Value	51,075	26,433
Less 12 Months Unrealized Losses	137	66
Total Fair Value	51,075	26,433
Total Unrealized Losses	137	66
US States and Political Subdivisions Debt Securities [Member]
Less 12 Months Fair Value	27,361	17,199
Less 12 Months Unrealized Losses	278	174
More 12 Months Fair Value	220
More 12 Months Unrealized Losses	1
Total Fair Value	27,581	17,199
Total Unrealized Losses	279	174
Residential Mortgage Backed Securities [Member]
Less 12 Months Fair Value	36,169	39,659
Less 12 Months Unrealized Losses	416	256
Total Fair Value	36,169	39,659
Total Unrealized Losses	416	256
Corporate Debt Securities [Member]
Less 12 Months Fair Value	382
Less 12 Months Unrealized Losses	2
More 12 Months Fair Value	5,211	4,994
More 12 Months Unrealized Losses	645	856
Total Fair Value	5,593	4,994
Total Unrealized Losses	647	856
Mutual Funds And Equity Securities [Member]
Less 12 Months Fair Value	261	299
Less 12 Months Unrealized Losses	2	2
Total Fair Value	261	299
Total Unrealized Losses	2	2
Total [Member]
Less 12 Months Fair Value	115,248	83,590
Less 12 Months Unrealized Losses	835	498
More 12 Months Fair Value	5,431	4,994
More 12 Months Unrealized Losses	646	856
Total Fair Value	120,679	88,584
Total Unrealized Losses	$ 1,481	$ 1,354