Note 6 - Loans Acquired - Nonaccrual Acquired Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans in nonaccrual status	$ 54,438	$ 39,104
Acquired Loans [Member]
Loans in nonaccrual status	23,700	46,832
Consumer Portfolio Segment [Member]
Loans in nonaccrual status	4,153	2,166
Consumer Portfolio Segment [Member] | Other Loans [Member]
Loans in nonaccrual status	3,880	1,793
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Loans in nonaccrual status	315	456
Consumer Portfolio Segment [Member] | Acquired Loans [Member] | Other Loans [Member]
Loans in nonaccrual status	315	456
Commercial Real Estate Portfolio Segment [Member]
Loans in nonaccrual status	34,248	27,935
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans in nonaccrual status	2,403	3,411
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Loans in nonaccrual status	13,034	12,139
Commercial Real Estate Portfolio Segment [Member] | Other Commercial Loans [Member]
Loans in nonaccrual status	18,811	12,385
Commercial Real Estate Portfolio Segment [Member] | Acquired Loans [Member]
Loans in nonaccrual status	21,006	43,372
Commercial Real Estate Portfolio Segment [Member] | Acquired Loans [Member] | Construction Loans [Member]
Loans in nonaccrual status	1,905	7,961
Commercial Real Estate Portfolio Segment [Member] | Acquired Loans [Member] | Single Family Residential Loans [Member]
Loans in nonaccrual status	11,840	13,366
Commercial Real Estate Portfolio Segment [Member] | Acquired Loans [Member] | Other Commercial Loans [Member]
Loans in nonaccrual status	7,261	22,045
Commercial Portfolio Segment [Member]
Loans in nonaccrual status	16,037	9,003
Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Loans in nonaccrual status	13,827	7,765
Commercial Portfolio Segment [Member] | Agricultural Loans [Member]
Loans in nonaccrual status	2,210	1,238
Commercial Portfolio Segment [Member] | Acquired Loans [Member]
Loans in nonaccrual status	2,379	3,004
Commercial Portfolio Segment [Member] | Acquired Loans [Member] | Commercial Loans [Member]
Loans in nonaccrual status	2,163	2,806
Commercial Portfolio Segment [Member] | Acquired Loans [Member] | Agricultural Loans [Member]
Loans in nonaccrual status	$ 216	$ 198