Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans	[1]	$ 1,672,901	$ 682,913
Consumer Portfolio Segment [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		75,606	8,514
Consumer Portfolio Segment [Member] | Other Loans [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		75,606	8,514
Commercial Real Estate Portfolio Segment [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		1,432,189	613,758
Commercial Real Estate Portfolio Segment [Member] | Other Loans [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		854,068	390,877
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		77,119	46,911
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		501,002	175,970
Commercial Portfolio Segment [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		165,106	60,641
Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		154,533	56,134
Commercial Portfolio Segment [Member] | Agricultural Loans [Member]
Note 5 - Loans Acquired (Details) - Carrying Value of all Acquired Impaired Loans [Line Items]
Acquired loans		$ 10,573	$ 4,507

[1] Loans acquired are reported net of a $954,000 allowance at December 31, 2015. Loans acquired include $106.9 million (net of a $954,000 allowance) of loans covered by FDIC loss share agreements at December 31, 2014.