Note 7 - Loans (Detail) - Schedule of Allowance for Loan Losses by Portfolio Segment and Based on Impairment Method (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	$ 5,607	$ 198,728
Balance collectively evaluated for impairment	275,230	6,737,239
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	189,136	7,552
Balance individually evaluated for impairment	6,633,314	321,973
Total allowance	194,743	206,280
Total balance	6,908,544	7,059,212
Commercial Portfolio Segment [Member]
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	1,272	62,322
Balance collectively evaluated for impairment	45,406	1,822,494
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	59,119	3,336
Balance individually evaluated for impairment	1,799,443	45,781
Total allowance	60,391	65,658
Total balance	1,844,849	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	43,426	158,606
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	17,993	0
Balance individually evaluated for impairment	144,655	78,766
Total allowance	17,993	21,749
Total balance	188,081	237,372
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	2,529	105,052
Balance collectively evaluated for impairment	168,753	3,571,839
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	103,657	2,969
Balance individually evaluated for impairment	3,493,683	177,058
Total allowance	106,186	108,021
Total balance	3,662,436	3,748,897
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Allowance collectively evaluated for impairment	1,806	9,548
Balance collectively evaluated for impairment	17,645	1,166,601
Loans collectively evaluated for impairment
Allowance individually evaluated for impairment	8,317	1,247
Balance individually evaluated for impairment	1,176,062	20,368
Total allowance	10,123	10,795
Total balance	1,193,707	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	50	0
Balance individually evaluated for impairment	19,471
Total allowance	50	57
Total balance	$ 19,471	$ 17,699