Note 6 - Loans Acquired (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Covered Purchased Impaired Loans Allowance	$ 391,000		$ 391,000			$ 954,000
Provision for Loan and Lease Losses	5,462,000	$ 8,294,000	16,792,000	$ 15,733,000
Acquired Loans [Member]
Non Covered Impaired Loans Allowance Reclassified	391,000		391,000			$ 954,000
Provision for Loan and Lease Losses	$ 0	215,000	$ 1,464,000	522,000
Hardeman County Investment Company, Inc. [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Net					$ 249,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Gross					254,300,000
Loans Acquired Discount					5,000,000
Hardeman County Investment Company, Inc. [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Net					2,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Gross					3,300,000
Loans Acquired Discount					$ 956,000
Citizens National Bank [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Net		340,100,000		340,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Gross		348,800,000		348,800,000
Loans Acquired Discount		8,700,000		8,700,000
Citizens National Bank [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Net		757,000		757,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Gross		1,600,000		1,600,000
Loans Acquired Discount		$ 848,000		$ 848,000