Note 20 - Estimated Fair Values and Related Carrying Amounts of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	$ 223,061	$ 252,262
Cash and Cash Equivalents [Member]
Assets	223,061	252,262
Assets, fair value	223,061	$ 252,262
Interest Bearing Balances Due from Banks - Time [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value
Interest Bearing Balances Due from Banks - Time [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	11,188	$ 14,105
Interest Bearing Balances Due from Banks - Time [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value
Interest Bearing Balances Due from Banks - Time [Member]
Assets	11,188	$ 14,107
Assets, fair value	11,188	14,105
Held-to-maturity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	686,835	713,371
Held-to-maturity Securities [Member]
Assets	674,502	705,373
Assets, fair value	686,835	713,371
Mortgage Loans Held For Sale [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	24,563	30,265
Mortgage Loans Held For Sale [Member]
Assets	24,563	30,265
Assets, fair value	24,563	30,265
Interest Receivable [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	23,545	25,793
Interest Receivable [Member]
Assets	23,545	25,793
Assets, fair value	23,545	25,793
Loans1 [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	3,427,771	3,204,153
Loans1 [Member]
Assets	3,440,010	3,215,103
Assets, fair value	$ 3,427,771	$ 3,204,153
Loans Acquired, Not Covered By FDIC Loss Share [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value
Liabilities, fair value
Loans Acquired, Not Covered By FDIC Loss Share [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value
Liabilities, fair value
Loans Acquired, Not Covered By FDIC Loss Share [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	$ 1,452,185
Liabilities, fair value		$ 1,667,204
Loans Acquired, Not Covered By FDIC Loss Share [Member]
Assets	1,457,370	1,672,901
Assets, fair value	1,452,185
Liabilities, fair value		1,667,204
Fair Value, Inputs, Level 2 [Member] | Non-Interest Bearing Transaction Accounts [Member]
Liabilities, fair value	1,274,816	1,280,234
Fair Value, Inputs, Level 2 [Member] | Interest Bearing Transaction Accounts and Savings Deposits [Member]
Liabilities, fair value	3,524,808	3,485,845
Fair Value, Inputs, Level 2 [Member] | Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Liabilities, fair value	97,429	99,398
Fair Value, Inputs, Level 2 [Member] | Other Borrowings [Member]
Liabilities, fair value	196,668	168,254
Fair Value, Inputs, Level 2 [Member] | Subordinated Debentures [Member]
Liabilities, fair value	54,803	55,954
Fair Value, Inputs, Level 2 [Member] | Interest Payable [Member]
Liabilities, fair value	1,864	1,800
Fair Value, Inputs, Level 3 [Member] | Time Deposits [Member]
Liabilities, fair value	1,277,555	1,315,254
Non-Interest Bearing Transaction Accounts [Member]
Liabilities	1,274,816	1,280,234
Liabilities, fair value	1,274,816	1,280,234
Interest Bearing Transaction Accounts and Savings Deposits [Member]
Liabilities	3,524,808	3,485,845
Liabilities, fair value	3,524,808	3,485,845
Time Deposits [Member]
Liabilities	1,280,151	1,320,017
Liabilities, fair value	1,277,555	1,315,254
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Liabilities	97,429	99,398
Liabilities, fair value	97,429	99,398
Other Borrowings [Member]
Liabilities	176,829	162,289
Liabilities, fair value	196,668	168,254
Subordinated Debentures [Member]
Liabilities	60,077	60,570
Liabilities, fair value	54,803	55,954
Interest Payable [Member]
Liabilities	1,864	1,800
Liabilities, fair value	1,864	1,800
Assets	7,536,953	7,559,658
Liabilities	$ 6,464,969	$ 6,482,803