Note 7 - Loans (Details) - Aging of Loan Portfolio (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 7,694,373	$ 7,429,147
Commercial Loans Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	7,644	16,832
60-89 Days Past Due	9,882	1,610
Greater than 90 Days Past Due		630
Non-accrual Loans	14,029	19,958
Total Past Due	31,555	39,030
Loans Not Past Due	2,179,206	2,088,077
Total	2,210,761	2,127,107
Real Estate Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	1,471
Greater than 90 Days Past Due	0	0
Non-accrual Loans	29,454	36,299
Total Past Due	29,454	37,770
Loans Not Past Due	124,209	143,180
Total	153,663	180,950
Commercial Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	24,860	21,570
60-89 Days Past Due	4,094	3,627
Greater than 90 Days Past Due	0	0
Non-accrual Loans	41,860	35,704
Total Past Due	70,814	60,901
Loans Not Past Due	3,838,745	3,707,551
Total	3,909,559	3,768,452
Residential Mortgage And Equity Lines Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,699	5,324
60-89 Days Past Due	1,315	1,972
Greater than 90 Days Past Due	0	0
Non-accrual Loans	10,270	11,941
Total Past Due	13,284	19,237
Loans Not Past Due	1,394,263	1,320,845
Total	1,407,547	1,340,082
Installment And Other Loans Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater than 90 Days Past Due	0	0
Non-accrual Loans	0	0
Total Past Due	0	0
Loans Not Past Due	12,843	12,556
Total	12,843	12,556
Total [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	34,203	43,726
60-89 Days Past Due	15,291	8,680
Greater than 90 Days Past Due		630
Non-accrual Loans	95,613	103,902
Total Past Due	145,107	156,938
Loans Not Past Due	7,549,266	7,272,209
Total	$ 7,694,373	$ 7,429,147