Note 5 - Loans and Allowance for Loan Losses (Detail) - Aging Analysis of Accruing and Non-Accruing Loans (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Commercial:
Financing Receivable - Past Due 90 Days or More	$ 2	$ 77
Financing Receivable	1,237,813	1,254,954
Financing Receivable - Nonaccrual	9,725	10,374
Purchased Credit Impaired Loans [Member] | Commercial and Industrial [Member]
Commercial:
Financing Receivable	6,543	7,323
Purchased Credit Impaired Loans [Member] | Commercial Real Estate Owner Occupied [Member]
Commercial:
Financing Receivable	42,068	44,925
Purchased Credit Impaired Loans [Member] | Commercial Real Estate Investor Income Producing [Member]
Commercial:
Financing Receivable	77,744	85,959
Purchased Credit Impaired Loans [Member] | Acquisition, Construction, and Development Portfolio [Member]
Commercial:
Financing Receivable	36,308	39,541
Purchased Credit Impaired Loans [Member] | Other Commercial [Member]
Commercial:
Financing Receivable	9	742
Purchased Credit Impaired Loans [Member] | Total Commercial [Member]
Commercial:
Financing Receivable	162,672	178,490
Purchased Credit Impaired Loans [Member] | Residential Mortgage Loans [Member]
Commercial:
Financing Receivable	39,100	40,483
Purchased Credit Impaired Loans [Member] | Home Equity Lines of Credit [Member]
Commercial:
Financing Receivable	1,955	1,949
Purchased Credit Impaired Loans [Member] | Residential Construction [Member]
Commercial:
Financing Receivable	10,596	11,265
Purchased Credit Impaired Loans [Member] | Other Loans to Individuals [Member]
Commercial:
Financing Receivable	1,640	2,095
Purchased Credit Impaired Loans [Member] | Total Consumer Loans [Member]
Commercial:
Financing Receivable	53,291	55,792
Purchased Credit Impaired Loans [Member] | Total [Member]
Commercial:
Financing Receivable	215,963	234,282
Commercial and Industrial [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	224	1,316
Financing Receivable - 60-89 Days Past Due	0	83
Financing Receivable - Past Due 90 Days or More	303	230
Financing Receivable - Nonaccrual	111,726	110,180
Financing Receivable - Current	118,796	119,132
Commercial Real Estate Owner Occupied [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	0	48
Financing Receivable - 60-89 Days Past Due	0	1,903
Financing Receivable - Past Due 90 Days or More	330	113
Financing Receivable - Nonaccrual	242,955	252,427
Financing Receivable - Current	285,353	299,416
Commercial Real Estate Investor Income Producing [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	67	224
Financing Receivable - 60-89 Days Past Due	8	27
Financing Receivable - Past Due 90 Days or More	232	366
Financing Receivable - Nonaccrual	289,383	285,381
Financing Receivable - Current	367,434	371,957
Acquisition, Construction, and Development Portfolio [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	556	0
Financing Receivable - 60-89 Days Past Due	138	699
Financing Receivable - Past Due 90 Days or More	1,185	1,428
Financing Receivable - Nonaccrual	102,682	98,993
Financing Receivable - Current	140,869	140,661
Other Commercial [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	204	0
Financing Receivable - 60-89 Days Past Due	0	0
Financing Receivable - Past Due 90 Days or More	0	168
Financing Receivable - Nonaccrual	4,681	4,718
Financing Receivable - Current	4,894	5,628
Total Commercial [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	1,051	1,588
Financing Receivable - 60-89 Days Past Due	146	2,712
Financing Receivable - Past Due 90 Days or More	2,050	2,305
Financing Receivable - Nonaccrual	751,427	751,699
Financing Receivable - Current	917,346	936,794
Residential Mortgage Loans [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	176	18
Financing Receivable - 60-89 Days Past Due	69	196
Financing Receivable - Past Due 90 Days or More	473	499
Financing Receivable - Nonaccrual	140,550	147,336
Financing Receivable - Current	180,368	188,532
Home Equity Lines of Credit [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	417	590
Financing Receivable - 60-89 Days Past Due	598	0
Financing Receivable - Past Due 90 Days or More	818	1,094
Financing Receivable - Nonaccrual	153,014	159,992
Financing Receivable - Current	156,802	163,625
Residential Construction [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	313	0
Financing Receivable - 60-89 Days Past Due	0	0
Financing Receivable - Past Due 90 Days or More	2	71
Financing Receivable - Nonaccrual	44,294	41,476
Financing Receivable - Current	55,205	52,812
Other Loans to Individuals [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	3	36
Financing Receivable - 60-89 Days Past Due	18	4
Financing Receivable - Past Due 90 Days or More	2	0
Financing Receivable - Nonaccrual	18,574	13,418
Financing Receivable - Current	20,237	15,553
Total Consumer Loans [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	909	644
Financing Receivable - 60-89 Days Past Due	685	200
Financing Receivable - Past Due 90 Days or More	1,295	1,664
Financing Receivable - Nonaccrual	356,432	362,222
Financing Receivable - Current	412,612	420,522
Total [Member]
Commercial:
Financing Receivable - 30-59 Days Past Due	1,960	2,232
Financing Receivable - 60-89 Days Past Due	831	2,912
Financing Receivable - Past Due 90 Days or More	3,345	3,969
Financing Receivable - Nonaccrual	1,107,859	1,113,921
Financing Receivable - Current	$ 1,329,958	$ 1,357,316