Note 5 - Loans (Detail) - Allowance for Loan Losses by Portfolio Segment and Based on Impairment Method (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	$ 12,183	$ 198,728
Balance individually evaluated for impairment	248,597	6,737,239
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	171,139	7,552
Balance collectively evaluated for impairment	7,180,550	321,973
Total allowance	183,322	206,280
Total balance	7,429,147	7,059,212
Commercial Portfolio Segment [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	1,467	62,322
Balance individually evaluated for impairment	23,922	1,822,494
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	64,634	3,336
Balance collectively evaluated for impairment	2,103,185	45,781
Total allowance	66,101	65,658
Total balance	2,127,107	1,868,275
Real Estate Construction Loans [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	8,158	21,749
Balance individually evaluated for impairment	42,133	158,606
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	14,859	0
Balance collectively evaluated for impairment	138,817	78,766
Total allowance	23,017	21,749
Total balance	180,950	237,372
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	1,336	105,052
Balance individually evaluated for impairment	165,885	3,571,839
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	81,137	2,969
Balance collectively evaluated for impairment	3,602,567	177,058
Total allowance	82,473	108,021
Total balance	3,768,452	3,748,897
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	1,222	9,548
Balance individually evaluated for impairment	16,657	1,166,601
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	10,481	1,247
Balance collectively evaluated for impairment	1,323,425	20,368
Total allowance	11,703	10,795
Total balance	1,340,082	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	28	0
Balance collectively evaluated for impairment	12,556	0
Total allowance	28	57
Total balance	$ 12,556	$ 17,699