Note 4 - Loans and Allowance for Credit Losses (Detail) - Impaired Loans (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Unpaid Contractual Principal Balance	$ 43,480	$ 48,096	$ 48,322
Recorded Investment With No Allowance	28,614	32,840	30,760
Recorded Investment With Allowance	14,366	10,258	15,237
Total Recorded Investment	42,980	43,098	45,997
Related Allowance	7,458	5,098	8,114
Average Recorded Investment	44,490	47,992	44,822
Interest Income Recognized	177	124	862
Commercial Loan [Member]
Unpaid Contractual Principal Balance	8,493	8,382	9,461
Recorded Investment With No Allowance	4,821	5,226	5,767
Recorded Investment With Allowance	3,172	1,891	3,481
Total Recorded Investment	7,993	7,117	9,248
Related Allowance	2,360	1,265	2,158
Average Recorded Investment	8,621	9,539	7,772
Interest Income Recognized	42	43	245
Commercial Real Estate Investment [Member]
Unpaid Contractual Principal Balance	5,407	9,155	5,600
Recorded Investment With No Allowance	3,821	6,277	3,830
Recorded Investment With Allowance	1,586	2,157	1,770
Total Recorded Investment	5,407	8,434	5,600
Related Allowance	818	821	1,201
Average Recorded Investment	5,504	10,330	6,609
Interest Income Recognized	37	39	152
Commercial Real Estate Owner Occupied [Member]
Unpaid Contractual Principal Balance	6,449	277	6,659
Recorded Investment With No Allowance	5,538		5,602
Recorded Investment With Allowance	911	207	1,057
Total Recorded Investment	6,449	207	6,659
Related Allowance	704	70	753
Average Recorded Investment	6,554	280	2,746
Interest Income Recognized	56		252
Residential Mortgage [Member]
Unpaid Contractual Principal Balance	691	731	699
Recorded Investment With No Allowance	691	731	699
Total Recorded Investment	691	731	699
Average Recorded Investment	695	886	714
Home Equity Line of Credit [Member]
Unpaid Contractual Principal Balance	481	530	513
Recorded Investment With No Allowance	132	307	134
Recorded Investment With Allowance	349	85	379
Total Recorded Investment	481	392	513
Related Allowance	218	138	243
Average Recorded Investment	497	577	534
Interest Income Recognized			9
Consumer, Other [Member]
Unpaid Contractual Principal Balance		8	43
Recorded Investment With No Allowance			1
Recorded Investment With Allowance		4	42
Total Recorded Investment		4	43
Related Allowance		4	41
Average Recorded Investment	22	8	17
Interest Income Recognized			2
Construction Loans [Member]
Unpaid Contractual Principal Balance	21,959	29,013	25,347
Recorded Investment With No Allowance	13,611	20,299	14,727
Recorded Investment With Allowance	8,348	5,914	8,508
Total Recorded Investment	21,959	26,213	23,235
Related Allowance	3,358	2,800	3,718
Average Recorded Investment	22,597	26,372	26,430
Interest Income Recognized	$ 42	$ 42	$ 202