Note 5 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment and Based on Impairment Method (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	$ 13,284	$ 171,139	$ 7,552
Balance individually evaluated for impairment	200,780	7,180,550	321,973
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	160,605	12,183	198,728
Balance collectively evaluated for impairment	7,883,783	248,597	6,737,239
Total allowance	173,889	183,322	206,280
Total balance	8,084,563	7,429,147	7,059,212
Commercial Portfolio Segment [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	2,519	64,634	3,336
Balance individually evaluated for impairment	31,968	2,103,185	45,781
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	62,584	1,467	62,322
Balance collectively evaluated for impairment	2,266,756	23,922	1,822,494
Total allowance	65,103	66,101	65,658
Total balance	2,298,724	2,127,107	1,868,275
Real Estate Construction Loans [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	3,460	14,859
Balance individually evaluated for impairment	34,420	138,817	78,766
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	8,539	8,158	21,749
Balance collectively evaluated for impairment	187,281	42,133	158,606
Total allowance	11,999	23,017	21,749
Total balance	221,701	180,950	237,372
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	6,584	81,137	2,969
Balance individually evaluated for impairment	114,544	3,602,567	177,058
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	78,169	1,336	105,052
Balance collectively evaluated for impairment	3,908,507	165,885	3,571,839
Total allowance	84,753	82,473	108,021
Total balance	4,023,051	3,768,452	3,748,897
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Allowance individually evaluated for impairment	721	10,481	1,247
Balance individually evaluated for impairment	19,848	1,323,425	20,368
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	11,284	1,222	9,548
Balance collectively evaluated for impairment	1,506,684	16,657	1,166,601
Total allowance	12,005	11,703	10,795
Total balance	1,526,532	1,340,082	1,186,969
Consumer And Other Member
Loans individually evaluated for impairment
Allowance individually evaluated for impairment		28
Balance individually evaluated for impairment		12,556
Loans collectively evaluated for impairment
Allowance collectively evaluated for impairment	29		57
Balance collectively evaluated for impairment	14,555		17,699
Total allowance	29	28	57
Total balance	$ 14,555	$ 12,556	$ 17,699