Note 9 - Fair Value Measurements (Details) - Fair Value Estimates for Financial Instruments, Excluding Financial Instruments Recorded at fair value on a recurring basis (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities held to maturity	$ 1,103,827	$ 1,112,676
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	428,840	472,028
Investment securities held to maturity	1,424	1,597
Financial Liabilities:
Federal Home Loan Bank advances	20,426	20,558
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities held to maturity	1,102,403	1,111,079
Financial Liabilities:
Deposits	3,757,214	3,671,014
Short-term borrowed funds	64,382	62,668
Term repurchase agreement	10,033	10,054
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,788,511	1,800,625
Other assets - FDIC indemnification receivable	5,610	4,032
Financial Liabilities:
Deposits	456,170	491,921
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	428,840	472,028
Investment securities held to maturity	1,110,329	1,132,299
Loans	1,784,210	1,796,051
Other assets - FDIC indemnification receivable	5,610	4,032
Financial Liabilities:
Deposits	4,214,783	4,163,781
Short-term borrowed funds	64,382	62,668
Federal Home Loan Bank advances	20,437	20,577
Term repurchase agreement	10,000	10,000
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	428,840	472,028
Investment securities held to maturity	1,103,827	1,112,676
Loans	1,788,511	1,800,625
Other assets - FDIC indemnification receivable	5,610	4,032
Financial Liabilities:
Deposits	4,213,384	4,162,935
Short-term borrowed funds	64,382	62,668
Federal Home Loan Bank advances	20,426	20,558
Term repurchase agreement	$ 10,033	$ 10,054