Note 5 - Loans and Allowance for Loan Losses (Detail) - Impaired Loans (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	$ 10,497		$ 15,795
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	26,467		23,175
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	13,939	11,645
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	41	28
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	6,755		1,947
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	7,009		2,187
Impaired Loans with an Allowance Recorded Related Allowance	1,637		715
Impaired Loans with an Allowance Recorded Average Recorded Investment	4,033	3,420
Impaired Loans with an Allowance Recorded Interest Income Recognized	45	9
Commercial:
Impaired Loans Recorded Investment	17,252		17,742
Impaired Loans Unpaid Principal Balance	33,476		25,362
Impaired Loans Related Allowance	1,637		715
Impaired Loans Average Recorded Investment	17,972	15,065
Impaired Loans Interest Income Recognized	86	37
Commercial and Industrial [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	380		377
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	1,065		1,170
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	536	639
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	1,245		230
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	1,245		230
Impaired Loans with an Allowance Recorded Related Allowance	767		115
Impaired Loans with an Allowance Recorded Average Recorded Investment	436	130
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	1,625		607
Impaired Loans Unpaid Principal Balance	2,310		1,400
Impaired Loans Related Allowance	767		115
Impaired Loans Average Recorded Investment	972	769
Impaired Loans Interest Income Recognized	0
Commercial Real Estate Owner Occupied [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	2,322		2,337
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	3,654		2,675
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	1,361	324
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	4	7
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	0		0
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	0		0
Impaired Loans with an Allowance Recorded Related Allowance	0		0
Impaired Loans with an Allowance Recorded Average Recorded Investment	12	0
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	2,322		2,337
Impaired Loans Unpaid Principal Balance	3,654		2,675
Impaired Loans Related Allowance	0		0
Impaired Loans Average Recorded Investment	1,373	324
Impaired Loans Interest Income Recognized	4	7
Commercial Real Estate Investor Income Producing [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	268		4,243
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	4,111		4,424
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	2,673	710
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	3,610		0
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	3,610		0
Impaired Loans with an Allowance Recorded Related Allowance	190		0
Impaired Loans with an Allowance Recorded Average Recorded Investment	1,411	1,378
Impaired Loans with an Allowance Recorded Interest Income Recognized	36
Commercial:
Impaired Loans Recorded Investment	3,878		4,243
Impaired Loans Unpaid Principal Balance	7,721		4,424
Impaired Loans Related Allowance	190		0
Impaired Loans Average Recorded Investment	4,084	2,088
Impaired Loans Interest Income Recognized	36
Acquisition, Construction, and Development Portfolio [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	3,547		4,855
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	10,445		9,306
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	6,726	8,954
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	18	21
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	0		0
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	0		0
Impaired Loans with an Allowance Recorded Related Allowance	0		0
Impaired Loans with an Allowance Recorded Average Recorded Investment	609	1,593
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	3,547		4,855
Impaired Loans Unpaid Principal Balance	10,445		9,306
Impaired Loans Related Allowance	0		0
Impaired Loans Average Recorded Investment	7,335	10,547
Impaired Loans Interest Income Recognized	18	21
Other Commercial [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	164		168
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	172		172
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	131	0
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	0		0
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	0		0
Impaired Loans with an Allowance Recorded Related Allowance	0		0
Impaired Loans with an Allowance Recorded Average Recorded Investment	0	0
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	164		168
Impaired Loans Unpaid Principal Balance	172		172
Impaired Loans Related Allowance	0		0
Impaired Loans Average Recorded Investment	131	0
Impaired Loans Interest Income Recognized	0
Total Commercial [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	6,681		11,980
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	19,447		17,747
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	11,427	10,627
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	22	28
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	4,855		230
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	4,855		230
Impaired Loans with an Allowance Recorded Related Allowance	957		115
Impaired Loans with an Allowance Recorded Average Recorded Investment	2,468	3,101
Impaired Loans with an Allowance Recorded Interest Income Recognized	36
Commercial:
Impaired Loans Recorded Investment	11,536		12,210
Impaired Loans Unpaid Principal Balance	24,302		17,977
Impaired Loans Related Allowance	957		115
Impaired Loans Average Recorded Investment	13,895	13,728
Impaired Loans Interest Income Recognized	58	28
Residential Mortgage Loans [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	2,358		2,252
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	3,058		2,363
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	1,341	409
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	18
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	1,201		1,211
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	1,248		1,250
Impaired Loans with an Allowance Recorded Related Allowance	247		249
Impaired Loans with an Allowance Recorded Average Recorded Investment	1,134	0
Impaired Loans with an Allowance Recorded Interest Income Recognized	9	9
Commercial:
Impaired Loans Recorded Investment	3,559		3,463
Impaired Loans Unpaid Principal Balance	4,306		3,613
Impaired Loans Related Allowance	247		249
Impaired Loans Average Recorded Investment	2,475	409
Impaired Loans Interest Income Recognized	27	9
Home Equity Lines of Credit [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	1,388		1,419
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	3,166		2,439
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	1,034	503
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	699		506
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	906		707
Impaired Loans with an Allowance Recorded Related Allowance	433		351
Impaired Loans with an Allowance Recorded Average Recorded Investment	431	319
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	2,087		1,925
Impaired Loans Unpaid Principal Balance	4,072		3,146
Impaired Loans Related Allowance	433		351
Impaired Loans Average Recorded Investment	1,465	822
Impaired Loans Interest Income Recognized	0
Residential Construction [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	2		71
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	693		551
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	78	94
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	0		0
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	0		0
Impaired Loans with an Allowance Recorded Related Allowance	0		0
Impaired Loans with an Allowance Recorded Average Recorded Investment	0	0
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	2		71
Impaired Loans Unpaid Principal Balance	693		551
Impaired Loans Related Allowance	0		0
Impaired Loans Average Recorded Investment	78	94
Impaired Loans Interest Income Recognized	0
Other Loans to Individuals [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	68		73
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	103		75
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	59	12
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	1
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	0		0
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	0		0
Impaired Loans with an Allowance Recorded Related Allowance	0		0
Impaired Loans with an Allowance Recorded Average Recorded Investment	0	0
Impaired Loans with an Allowance Recorded Interest Income Recognized	0
Commercial:
Impaired Loans Recorded Investment	68		73
Impaired Loans Unpaid Principal Balance	103		75
Impaired Loans Related Allowance	0		0
Impaired Loans Average Recorded Investment	59	12
Impaired Loans Interest Income Recognized	1
Total Consumer Loans [Member]
Commercial:
Impaired Loans with No Related Allowance Recorded Recorded Investment	3,816		3,815
Impaired Loans with No Related Allowance Recorded Unpaid Principal Balance	7,020		5,428
Impaired Loans with No Related Allowance Recorded Average Recorded Investment	2,512	1,018
Impaired Loans with No Related Allowance Recorded Interest Income Recognized	19
Commercial:
Impaired Loans with an Allowance Recorded Recorded Investment	1,900		1,717
Impaired Loans with an Allowance Recorded Unpaid Principal Balance	2,154		1,957
Impaired Loans with an Allowance Recorded Related Allowance	680		600
Impaired Loans with an Allowance Recorded Average Recorded Investment	1,565	319
Impaired Loans with an Allowance Recorded Interest Income Recognized	9	9
Commercial:
Impaired Loans Recorded Investment	5,716		5,532
Impaired Loans Unpaid Principal Balance	9,174		7,385
Impaired Loans Related Allowance	680		600
Impaired Loans Average Recorded Investment	4,077	1,337
Impaired Loans Interest Income Recognized	$ 28	$ 9