Note 7 - Loans (Details) - Aging of Loan Portfolio (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Type of Loans:
Total	$ 8,565,278	$ 8,084,563
Commercial Loans [Member]
Type of Loans:
30-59 Days Past Due	14,384	7,170
60-89 Days Past Due	4	16,562
Non-accrual Loans	11,570	21,232
Total Past Due	25,958	44,964
Loans Not Past Due	2,296,922	2,253,760
Total	2,322,880	2,298,724
Real Estate Construction Loans [Member]
Type of Loans:
Non-accrual Loans	25,928	28,586
Total Past Due	25,928	28,586
Loans Not Past Due	259,411	193,115
Total	285,339	221,701
Commercial Mortgage Loans [Member]
Type of Loans:
30-59 Days Past Due	564	20,043
60-89 Days Past Due	12,321	7,862
Greater than 90 Days Past Due	1,426	982
Non-accrual Loans	30,549	19,621
Total Past Due	44,860	48,508
Loans Not Past Due	4,263,310	3,974,543
Total	4,308,170	4,023,051
Residential Mortgage And Equity Lines Member
Type of Loans:
30-59 Days Past Due	274	3,508
60-89 Days Past Due	1,128	832
Non-accrual Loans	9,526	13,744
Total Past Due	10,928	18,084
Loans Not Past Due	1,628,498	1,508,448
Total	1,639,426	1,526,532
Installment And Other Loans [Member]
Type of Loans:
30-59 Days Past Due	39	100
Total Past Due	39	100
Loans Not Past Due	9,424	14,455
Total	9,463	14,555
Total [Member]
Type of Loans:
30-59 Days Past Due	15,261	30,821
60-89 Days Past Due	13,453	25,256
Greater than 90 Days Past Due	1,426	982
Non-accrual Loans	77,573	83,183
Total Past Due	107,713	140,242
Loans Not Past Due	8,457,565	7,944,321
Total	$ 8,565,278	$ 8,084,563