Note 18 - Fair Value Measurements (Detail) - Estimated Fair Values and Related Carrying Amounts of Financial Instruments, as of September 30, 2012 (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financial assets:
Financial Assets, Carrying Amount	$ 3,414,980	$ 3,320,129
Financial liabilities:
Financial Liabilities, Carrying Amount	3,010,732	2,912,218
Non-Interest Bearing Transaction Accounts [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	543,380
Non-Interest Bearing Transaction Accounts [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	543,380	532,259
Non-Interest Bearing Transaction Accounts [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	543,380	532,259
Interest Bearing Transaction Accounts and Savings Deposits [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	1,343,784
Interest Bearing Transaction Accounts and Savings Deposits [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	1,343,784	1,239,504
Interest Bearing Transaction Accounts and Savings Deposits [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	1,343,784	1,239,504
Time Deposits [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	813,086
Time Deposits [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	813,086	882,244
Time Deposits [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	908,131	878,634
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	64,829
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	64,829	114,766
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	64,829	114,766
Other Borrowings [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	94,866
Other Borrowings [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	94,866	96,129
Other Borrowings [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	88,852	90,170
Subordinated Debentures [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	15,499
Subordinated Debentures [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	15,499	30,833
Subordinated Debentures [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	20,620	30,930
Interet Payable [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	1,693
Interet Payable [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial liabilities:
Financial Liabilities, Fair Value Measurement	1,693	1,437
Interet Payable [Member]
Financial liabilities:
Financial Liabilities, Carrying Amount	1,693	1,437
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	488,451
Cash and Cash Equivalents [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	488,451	570,206
Cash and Cash Equivalents [Member]
Financial assets:
Financial Assets, Carrying Amount	488,451	570,206
Held-to-Maturity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	516,419
Held-to-Maturity Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	516,419	532,206
Held-to-Maturity Securities [Member]
Financial assets:
Financial Assets, Carrying Amount	510,630	525,444
Mortgage Loans Held For Sale [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	23,980
Mortgage Loans Held For Sale [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	23,980	22,976
Mortgage Loans Held For Sale [Member]
Financial assets:
Financial Assets, Carrying Amount	23,980	22,976
Interest Receivable [Member] | Fair Value, Inputs, Level 2 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	15,253
Interest Receivable [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	15,253	15,126
Interest Receivable [Member]
Financial assets:
Financial Assets, Carrying Amount	15,253	15,126
Loans1 [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	1,593,995
Loans1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	1,593,995
Loans1 [Member]
Financial assets:
Financial Assets, Carrying Amount	1,623,401
Loans Acquired, Covered By FDIC Loss Share [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	162,335
Loans Acquired, Covered By FDIC Loss Share [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	162,335
Loans Acquired, Covered By FDIC Loss Share [Member]
Financial assets:
Financial Assets, Carrying Amount	163,657
Loans Acquired, Not Covered By FDIC Loss Share [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	73,023
Loans Acquired, Not Covered By FDIC Loss Share [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	73,023
Loans Acquired, Not Covered By FDIC Loss Share [Member]
Financial assets:
Financial Assets, Carrying Amount	73,023
FDIC Indemnification Asset [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets:
Financial Assets, Fair Value Measurement	59,547
FDIC Indemnification Asset [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets:
Financial Assets, Fair Value Measurement	59,547	47,683
FDIC Indemnification Asset [Member]
Financial assets:
Financial Assets, Carrying Amount	$ 59,547	$ 47,683