Note 7 - Loans (Detail) - Allowance for Loan Losses by Portfolio Segment and Based on Impairment Method (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	$ 7,242	$ 198,728
Balance collectively evaluated for impairment	276,571	6,737,239
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	185,032	7,552
Balance individually evaluated for impairment	6,767,112	321,973
Total allowance	192,274	206,280
Total balance	7,043,683	7,059,212
Commercial Portfolio Segment [Member]
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	3,687	62,322
Balance collectively evaluated for impairment	28,404	1,822,494
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	62,908	3,336
Balance individually evaluated for impairment	1,917,316	45,781
Total allowance	66,595	65,658
Total balance	1,945,720	1,868,275
Real Estate Construction Loans [Member]
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	0	21,749
Balance collectively evaluated for impairment	44,622	158,606
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	16,360	0
Balance individually evaluated for impairment	135,464	78,766
Total allowance	16,360	21,749
Total balance	180,086	237,372
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	1,896	105,052
Balance collectively evaluated for impairment	184,683	3,571,839
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	97,113	2,969
Balance individually evaluated for impairment	3,510,757	177,058
Total allowance	99,009	108,021
Total balance	3,695,440	3,748,897
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	1,659	9,548
Balance collectively evaluated for impairment	18,862	1,166,601
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	8,595	1,247
Balance individually evaluated for impairment	1,186,902	20,368
Total allowance	10,254	10,795
Total balance	1,205,764	1,186,969
Consumer And Other Member
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	0	57
Balance collectively evaluated for impairment	0	17,699
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	56	0
Balance individually evaluated for impairment	16,673
Total allowance	56	57
Total balance	$ 16,673	$ 17,699