Note 7 - Loans (Detail) - Schedule of Allowance for Loan Losses by Portfolio Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Provision for possible credit losses	$ 2,740	$ 1,979
Commercial Loans Member
Beginning Balance	65,658	63,919
Provision for possible credit losses	(1,041)	(122)
Charge-offs	(4,959)	(1,378)
Recoveries	746	775
Net charge-offs	(4,213)	(603)
Ending Balance	60,404	63,194
Reserve for impaired loans	1,272	2,953
Reserve for non-impaired loans	59,119	60,241
Reserve for off-balance sheet credit commitments	720	689
Real Estate Construction Loans [Member]
Beginning Balance	21,749	43,261
Provision for possible credit losses	(6,439)	4,654
Charge-offs	(875)	(6,248)
Recoveries	3,557	887
Net charge-offs	2,682	(5,361)
Ending Balance	17,992	42,554
Reserve for impaired loans	0	7,569
Reserve for non-impaired loans	17,993	34,985
Reserve for off-balance sheet credit commitments	635	1,355
Commercial Mortgage Loans [Member]
Beginning Balance	108,021	128,347
Provision for possible credit losses	4,318	1,218
Charge-offs	(8,222)	(5,123)
Recoveries	2,058	853
Net charge-offs	(6,164)	(4,270)
Ending Balance	106,175	125,295
Reserve for impaired loans	2,529	3,664
Reserve for non-impaired loans	103,657	121,631
Reserve for off-balance sheet credit commitments	84	93
Residential Mortgage And Equity Lines Member
Beginning Balance	10,795	9,668
Provision for possible credit losses	(260)	423
Charge-offs	(779)	(226)
Recoveries	366	84
Net charge-offs	(413)	(142)
Ending Balance	10,122	9,949
Reserve for impaired loans	1,806	1,106
Reserve for non-impaired loans	8,317	8,843
Reserve for off-balance sheet credit commitments	34	35
Installment And Other Loans Member
Beginning Balance	57	36
Provision for possible credit losses	15	(10)
Charge-offs	(25)
Recoveries	3	12
Net charge-offs	(22)	12
Ending Balance	50	38
Reserve for impaired loans	0
Reserve for non-impaired loans	50	38
Reserve for off-balance sheet credit commitments	2	2
Total [Member]
Beginning Balance	206,280	245,231
Provision for possible credit losses	(3,407)	6,163
Charge-offs	(14,860)	(12,975)
Recoveries	6,730	2,611
Net charge-offs	(8,130)	(10,364)
Ending Balance	194,743	241,030
Reserve for impaired loans	5,607	15,292
Reserve for non-impaired loans	189,136	225,738
Reserve for off-balance sheet credit commitments	$ 1,475	$ 2,174