Note 7 - Loans (Detail) - Allowance for Loan Losses by Portfolio Segment and Based on Impairment Method (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	$ 5,425	$ 198,728
Balance individually evaluated for impairment	265,096	6,737,239
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	179,013	7,552
Balance collectively evaluated for impairment	6,994,834	321,973
Total allowance	184,438	206,280
Total balance	7,259,930	7,059,212
Commercial Portfolio Segment [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	1,791	62,322
Balance individually evaluated for impairment	27,051	1,822,494
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	63,947	3,336
Balance collectively evaluated for impairment	2,055,869	45,781
Total allowance	65,738	65,658
Total balance	2,082,920	1,868,275
Real Estate Construction Loans [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	279	21,749
Balance individually evaluated for impairment	41,656	158,606
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	15,849	0
Balance collectively evaluated for impairment	145,592	78,766
Total allowance	16,128	21,749
Total balance	187,248	237,372
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	1,729	105,052
Balance individually evaluated for impairment	178,409	3,571,839
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	90,282	2,969
Balance collectively evaluated for impairment	3,526,368	177,058
Total allowance	92,011	108,021
Total balance	3,704,777	3,748,897
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	1,626	9,548
Balance individually evaluated for impairment	17,980	1,166,601
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	8,902	1,247
Balance collectively evaluated for impairment	1,255,303	20,368
Total allowance	10,528	10,795
Total balance	1,273,283	1,186,969
Consumer And Other Member
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	0	57
Balance individually evaluated for impairment	0	17,699
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	33	0
Balance collectively evaluated for impairment	11,702	0
Total allowance	33	57
Total balance	$ 11,702	$ 17,699