Note 2 - Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	May 15, 2017	Sep. 09, 2016	Sep. 30, 2017	Dec. 31, 2016
Goodwill			$ 375,731	$ 348,505
Hardeman County Investment Company, Inc. [Member]
Cash and due from banks	$ 8,001
Interest bearing balances due from banks - time	1,984
Investment securities	170,338
Loans acquired	251,649
Foreclosed assets	631
Premises and equipment	11,163
Bank owned life insurance	7,819
Goodwill	29,402
Other assets	2,638
Total assets acquired	462,893
Non-interest bearing transaction accounts	76,555
Interest bearing transaction accounts and savings deposits	214,872
Time deposits	97,549
Total deposits	388,976
Securities sold under agreement to repurchase	17,163
Other borrowings	3,000
Subordinated debentures	6,702
Accrued interest and other liabilities	3,815
Total liabilities assumed	419,656
Equity
Total liabilities and equity assumed	419,656
Net assets acquired	43,237
Purchase price	72,639
Hardeman County Investment Company, Inc. [Member] | Core Deposit Premium [Member]
Intangibles	7,840
Hardeman County Investment Company, Inc. [Member] | Other Intangible Assets [Member]
Intangibles	830
Hardeman County Investment Company, Inc. [Member] | Cost Acquired [Member]
Cash and due from banks	8,001
Interest bearing balances due from banks - time	1,984
Investment securities	170,654
Loans acquired	257,641
Allowance for loan losses	(2,382)
Foreclosed assets	1,083
Premises and equipment	9,905
Bank owned life insurance	7,819
Goodwill	11,485
Other assets	2,639
Total assets acquired	468,829
Non-interest bearing transaction accounts	76,555
Interest bearing transaction accounts and savings deposits	214,872
Time deposits	97,917
Total deposits	389,344
Securities sold under agreement to repurchase	17,163
Other borrowings	3,000
Subordinated debentures	6,702
Accrued interest and other liabilities	1,891
Total liabilities assumed	418,100
Equity	50,729
Total liabilities and equity assumed	468,829
Hardeman County Investment Company, Inc. [Member] | Fair Value Adjustments [Member]
Cash and due from banks
Interest bearing balances due from banks - time
Investment securities	(316)
Loans acquired	(5,992)
Allowance for loan losses	2,382
Foreclosed assets	(452)
Premises and equipment	1,258
Goodwill	(11,485)
Other assets	(1)
Total assets acquired	(5,936)
Non-interest bearing transaction accounts
Interest bearing transaction accounts and savings deposits
Time deposits	(368)
Total deposits	(368)
Securities sold under agreement to repurchase
Other borrowings
Subordinated debentures
Accrued interest and other liabilities	1,924
Total liabilities assumed	1,556
Equity	(50,729)
Total liabilities and equity assumed	(49,173)
Hardeman County Investment Company, Inc. [Member] | Fair Value Adjustments [Member] | Core Deposit Premium [Member]
Intangibles	7,840
Hardeman County Investment Company, Inc. [Member] | Fair Value Adjustments [Member] | Other Intangible Assets [Member]
Intangibles	$ 830
Citizens National Bank [Member]
Cash and due from banks		$ 131,116
Investment securities		61,988
Loans acquired		340,850
Allowance for loan losses
Foreclosed assets		3,442
Premises and equipment		8,085
Bank owned life insurance		6,632
Goodwill		23,376
Other assets		17,370
Total assets acquired		585,149
Non-interest bearing transaction accounts		109,281
Interest bearing transaction accounts and savings deposits		204,912
Time deposits		195,664
Total deposits		509,857
Securities sold under agreement to repurchase		13,233
Accrued interest and other liabilities		5,088
Total liabilities assumed		532,225
Equity
Total liabilities and equity assumed		532,225
Net assets acquired		52,924
Purchase price		76,300
Federal funds sold		10,000
FHLB borrowings		4,047
Citizens National Bank [Member] | Core Deposit Premium [Member]
Intangibles		5,075
Citizens National Bank [Member] | Other Intangible Assets [Member]
Intangibles		591
Citizens National Bank [Member] | Cost Acquired [Member]
Cash and due from banks		131,467
Investment securities		61,987
Loans acquired		350,361
Allowance for loan losses		(4,313)
Foreclosed assets		4,960
Premises and equipment		6,746
Bank owned life insurance		6,632
Other assets		17,364
Total assets acquired		585,204
Non-interest bearing transaction accounts		109,281
Interest bearing transaction accounts and savings deposits		204,912
Time deposits		195,664
Total deposits		509,857
Securities sold under agreement to repurchase		13,233
Accrued interest and other liabilities		3,558
Total liabilities assumed		530,648
Equity		54,556
Total liabilities and equity assumed		585,204
Federal funds sold		10,000
FHLB borrowings		4,000
Citizens National Bank [Member] | Cost Acquired [Member] | Core Deposit Premium [Member]
Intangibles
Citizens National Bank [Member] | Cost Acquired [Member] | Other Intangible Assets [Member]
Intangibles
Citizens National Bank [Member] | Fair Value Adjustments [Member]
Cash and due from banks		(351)
Investment securities		1
Loans acquired		(9,511)
Allowance for loan losses		4,313
Foreclosed assets		(1,518)
Premises and equipment		1,339
Bank owned life insurance
Other assets		6
Total assets acquired		(55)
Non-interest bearing transaction accounts
Interest bearing transaction accounts and savings deposits
Time deposits
Total deposits
Securities sold under agreement to repurchase
Accrued interest and other liabilities		1,530
Total liabilities assumed		1,577
Equity		(54,556)
Total liabilities and equity assumed		(52,979)
Federal funds sold
FHLB borrowings		47
Citizens National Bank [Member] | Fair Value Adjustments [Member] | Core Deposit Premium [Member]
Intangibles		5,075
Citizens National Bank [Member] | Fair Value Adjustments [Member] | Other Intangible Assets [Member]
Intangibles		$ 591