Note 4 - Loans and Allowance for Credit Losses (Detail) - Impaired Loans (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Unpaid Contractual Principal Balance	$ 41,206	$ 44,045	$ 46,667
Recorded Investment With No Allowance	23,802	20,925	28,713
Recorded Investment With Allowance	17,404	23,120	17,954
Total Recorded Investment	41,206	44,045	46,667
Related Allowance	7,297	4,594	5,079
Commercial Loan [Member] | Quarter to Date [Member]
Average Recorded Investment	6,622	7,696
Interest Income Recognized	48	255
Commercial Loan [Member] | Year to Date [Member]
Average Recorded Investment	8,080	5,426	7,955
Interest Income Recognized	94	255	161
Commercial Loan [Member]
Unpaid Contractual Principal Balance	7,282	10,742	10,695
Recorded Investment With No Allowance	3,587	6,390	2,723
Recorded Investment With Allowance	3,695	4,352	7,972
Total Recorded Investment	7,282	10,742	10,695
Related Allowance	2,256	1,933	2,249
Commercial Real Estate Investment [Member] | Quarter to Date [Member]
Average Recorded Investment	5,840	7,306
Interest Income Recognized	38	117
Commercial Real Estate Investment [Member] | Year to Date [Member]
Average Recorded Investment	8,010	5,876	8,298
Interest Income Recognized	114	117	159
Commercial Real Estate Investment [Member]
Unpaid Contractual Principal Balance	5,789	6,750	11,205
Recorded Investment With No Allowance	3,830	3,685	8,222
Recorded Investment With Allowance	1,959	3,065	2,983
Total Recorded Investment	5,789	6,750	11,205
Related Allowance	863	759	724
Commercial Real Estate Owner Occupied [Member] | Quarter to Date [Member]
Average Recorded Investment	2,024	688
Interest Income Recognized	39	4
Commercial Real Estate Owner Occupied [Member] | Year to Date [Member]
Average Recorded Investment	1,152	385	488
Interest Income Recognized	39	4	6
Commercial Real Estate Owner Occupied [Member]
Unpaid Contractual Principal Balance	2,374	1,080	282
Recorded Investment With No Allowance	1,315	791
Recorded Investment With Allowance	1,059	289	282
Total Recorded Investment	2,374	1,080	282
Related Allowance	413	90	90
Residential Mortgage [Member] | Quarter to Date [Member]
Average Recorded Investment	714	1,048
Interest Income Recognized		16
Residential Mortgage [Member] | Year to Date [Member]
Average Recorded Investment	800	1,042	1,112
Interest Income Recognized		16	24
Residential Mortgage [Member]
Unpaid Contractual Principal Balance	713	1,049	1,041
Recorded Investment With No Allowance	713	1,049	8
Recorded Investment With Allowance			1,033
Total Recorded Investment	713	1,049	1,041
Related Allowance			300
Home Equity Line of Credit [Member] | Quarter to Date [Member]
Average Recorded Investment	547	655
Interest Income Recognized	8	12
Home Equity Line of Credit [Member] | Year to Date [Member]
Average Recorded Investment	562	366	557
Interest Income Recognized	8	12	19
Home Equity Line of Credit [Member]
Unpaid Contractual Principal Balance	670	664	624
Recorded Investment With No Allowance	132	240	353
Recorded Investment With Allowance	538	424	271
Total Recorded Investment	670	664	624
Related Allowance	380	283	182
Consumer, Other [Member] | Quarter to Date [Member]
Average Recorded Investment	8	9
Consumer, Other [Member] | Year to Date [Member]
Average Recorded Investment	8	3	6
Consumer, Other [Member]
Unpaid Contractual Principal Balance	7	8	8
Recorded Investment With Allowance	7	8	8
Total Recorded Investment	7	8	8
Related Allowance	4	4	4
Quarter to Date [Member] | Construction Loans [Member]
Average Recorded Investment	25,680	22,445
Interest Income Recognized	56	171
Quarter to Date [Member]
Average Recorded Investment	41,435	39,847
Interest Income Recognized	189	575
Year to Date [Member] | Construction Loans [Member]
Average Recorded Investment	25,796	19,286	22,254
Interest Income Recognized	139	171	14
Year to Date [Member]
Average Recorded Investment	44,408	32,384	40,670
Interest Income Recognized	394	575	383
Construction Loans [Member]
Unpaid Contractual Principal Balance	24,371	23,752	22,812
Recorded Investment With No Allowance	14,225	8,770	17,407
Recorded Investment With Allowance	10,146	14,982	5,405
Total Recorded Investment	24,371	23,752	22,812
Related Allowance	$ 3,381	$ 1,525	$ 1,530