Note 7 - Loans (Detail) - Aging of Loan Portfolio (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Total	$ 7,259,930	$ 7,059,212
Commercial Loans Member
30-59 Days Past Due	4,498	1,683
60-89 Days Past Due	2,930	0
Greater than 90 Days Past Due	0	0
Non-accrual Loans	23,035	30,661
Total Past Due	30,463	32,344
Loans Not Past Due	2,052,457	1,835,931
Total	2,082,920	1,868,275
Real Estate Construction Loans [Member]
30-59 Days Past Due		20,326
60-89 Days Past Due	17,095	0
Greater than 90 Days Past Due	0	0
Non-accrual Loans	9,422	46,012
Total Past Due	26,517	66,338
Loans Not Past Due	160,731	171,034
Total	187,248	237,372
Commercial Mortgage Loans [Member]
30-59 Days Past Due	8,424	13,627
60-89 Days Past Due	6,523	20,277
Greater than 90 Days Past Due	0	6,726
Non-accrual Loans	48,754	107,784
Total Past Due	63,701	148,414
Loans Not Past Due	3,641,076	3,600,483
Total	3,704,777	3,748,897
Residential Mortgage And Equity Lines Member
30-59 Days Past Due	344	5,871
60-89 Days Past Due	4,006	0
Greater than 90 Days Past Due	0	0
Non-accrual Loans	13,733	16,740
Total Past Due	18,083	22,611
Loans Not Past Due	1,255,200	1,164,358
Total	1,273,283	1,186,969
Installment And Other Loans Member
30-59 Days Past Due	0	0
60-89 Days Past Due	40	0
Greater than 90 Days Past Due	0	0
Non-accrual Loans	0	0
Total Past Due	40	0
Loans Not Past Due	11,662	17,699
Total	11,702	17,699
Total [Member]
30-59 Days Past Due	13,266	41,507
60-89 Days Past Due	30,594	20,277
Greater than 90 Days Past Due		6,726
Non-accrual Loans	94,944	201,197
Total Past Due	138,804	269,707
Loans Not Past Due	7,121,126	6,789,505
Total	$ 7,259,930	$ 7,059,212