Note 5 - Loans Acquired - Summary of Acquired Loans, Excluding Loans Covered by Loss Share (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Balance, end of period	$ 5,632,890	$ 4,919,355
Pass [Member]
Balance, end of period	5,433,036	4,745,322
Special Mention [Member]
Balance, end of period	33,865	20,334
Substandard [Member]
Balance, end of period	164,251	148,719
Doubtful [Member]
Balance, end of period	1,715	4,521
Unlikely to be Collected Financing Receivable [Member]
Balance, end of period	23	459
Acquired Loans [Member]
Balance, end of period	1,305,683	1,672,901
Acquired Loans [Member] \| Pass [Member]
Balance, end of period	1,217,886	1,590,384
Acquired Loans [Member] \| Special Mention [Member]
Balance, end of period	22,181	9,150
Acquired Loans [Member] \| Substandard [Member]
Balance, end of period	64,075	69,219
Acquired Loans [Member] \| Doubtful [Member]
Balance, end of period	1,541	3,689
Acquired Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period		459
Consumer Portfolio Segment [Member]
Balance, end of period	488,563	385,668
Consumer Portfolio Segment [Member] \| Pass [Member]
Balance, end of period	485,575	383,878
Consumer Portfolio Segment [Member] \| Special Mention [Member]
Balance, end of period	26
Consumer Portfolio Segment [Member] \| Substandard [Member]
Balance, end of period	2,962	1,741
Consumer Portfolio Segment [Member] \| Doubtful [Member]
Balance, end of period		49
Consumer Portfolio Segment [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Balance, end of period	303,972	208,380
Consumer Portfolio Segment [Member] \| Other Loans [Member] \| Pass [Member]
Balance, end of period	301,632	207,069
Consumer Portfolio Segment [Member] \| Other Loans [Member] \| Special Mention [Member]
Balance, end of period	26
Consumer Portfolio Segment [Member] \| Other Loans [Member] \| Substandard [Member]
Balance, end of period	2,314	1,262
Consumer Portfolio Segment [Member] \| Other Loans [Member] \| Doubtful [Member]
Balance, end of period		49
Consumer Portfolio Segment [Member] \| Other Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Consumer Portfolio Segment [Member] \| Acquired Loans [Member]
Balance, end of period	49,677	75,606
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Pass [Member]
Balance, end of period	48,992	75,330
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Special Mention [Member]
Balance, end of period	14
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Substandard [Member]
Balance, end of period	671	276
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Doubtful [Member]
Balance, end of period
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member]
Balance, end of period	49,677	75,606
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Pass [Member]
Balance, end of period	48,992	75,330
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Special Mention [Member]
Balance, end of period	14
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Substandard [Member]
Balance, end of period	671	276
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Doubtful [Member]
Balance, end of period
Consumer Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member]
Balance, end of period	3,028,079	2,204,992
Commercial Real Estate Portfolio Segment [Member] \| Pass [Member]
Balance, end of period	2,943,890	2,128,687
Commercial Real Estate Portfolio Segment [Member] \| Special Mention [Member]
Balance, end of period	10,996	8,424
Commercial Real Estate Portfolio Segment [Member] \| Substandard [Member]
Balance, end of period	73,019	67,104
Commercial Real Estate Portfolio Segment [Member] \| Doubtful [Member]
Balance, end of period	174	777
Commercial Real Estate Portfolio Segment [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Balance, end of period	336,759	279,740
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Pass [Member]
Balance, end of period	330,080	270,386
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Special Mention [Member]
Balance, end of period	98	319
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Substandard [Member]
Balance, end of period	6,565	9,019
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Doubtful [Member]
Balance, end of period	16	16
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member] \| Single Family Residential Loans [Member]
Balance, end of period	904,245	696,180
Commercial Real Estate Portfolio Segment [Member] \| Single Family Residential Loans [Member] \| Pass [Member]
Balance, end of period	875,603	679,484
Commercial Real Estate Portfolio Segment [Member] \| Single Family Residential Loans [Member] \| Special Mention [Member]
Balance, end of period	4,024	2,701
Commercial Real Estate Portfolio Segment [Member] \| Single Family Residential Loans [Member] \| Substandard [Member]
Balance, end of period	24,460	13,824
Commercial Real Estate Portfolio Segment [Member] \| Single Family Residential Loans [Member] \| Doubtful [Member]
Balance, end of period	158	171
Commercial Real Estate Portfolio Segment [Member] \| Single Family Residential Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member]
Balance, end of period	1,170,871	1,432,189
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Pass [Member]
Balance, end of period	1,092,275	1,360,505
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Special Mention [Member]
Balance, end of period	20,168	8,818
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Substandard [Member]
Balance, end of period	56,893	60,732
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Doubtful [Member]
Balance, end of period	1,535	1,675
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period		459
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member]
Balance, end of period	690,108	854,068
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Pass [Member]
Balance, end of period	641,018	812,537
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Special Mention [Member]
Balance, end of period	17,384	7,328
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Substandard [Member]
Balance, end of period	31,706	33,748
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Doubtful [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Other Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period		455
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Construction Loans [Member]
Balance, end of period	57,587	77,119
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Construction Loans [Member] \| Pass [Member]
Balance, end of period	50,704	68,775
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Construction Loans [Member] \| Special Mention [Member]
Balance, end of period	88
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Construction Loans [Member] \| Substandard [Member]
Balance, end of period	6,795	8,344
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Construction Loans [Member] \| Doubtful [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Construction Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Single Family Residential Loans [Member]
Balance, end of period	423,176	501,002
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Single Family Residential Loans [Member] \| Pass [Member]
Balance, end of period	400,553	479,193
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Single Family Residential Loans [Member] \| Special Mention [Member]
Balance, end of period	2,696	1,490
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Single Family Residential Loans [Member] \| Substandard [Member]
Balance, end of period	18,392	18,640
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Single Family Residential Loans [Member] \| Doubtful [Member]
Balance, end of period	1,535	1,675
Commercial Real Estate Portfolio Segment [Member] \| Acquired Loans [Member] \| Single Family Residential Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period		4
Commercial Portfolio Segment [Member]
Balance, end of period	789,903	648,679
Commercial Portfolio Segment [Member] \| Pass [Member]
Balance, end of period	765,023	635,351
Commercial Portfolio Segment [Member] \| Special Mention [Member]
Balance, end of period	662	2,760
Commercial Portfolio Segment [Member] \| Substandard [Member]
Balance, end of period	24,195	10,562
Commercial Portfolio Segment [Member] \| Doubtful [Member]
Balance, end of period		6
Commercial Portfolio Segment [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period	23
Commercial Portfolio Segment [Member] \| Commercial Loans [Member]
Balance, end of period	639,525	500,116
Commercial Portfolio Segment [Member] \| Commercial Loans [Member] \| Pass [Member]
Balance, end of period	616,805	487,563
Commercial Portfolio Segment [Member] \| Commercial Loans [Member] \| Special Mention [Member]
Balance, end of period	558	2,760
Commercial Portfolio Segment [Member] \| Commercial Loans [Member] \| Substandard [Member]
Balance, end of period	22,162	9,787
Commercial Portfolio Segment [Member] \| Commercial Loans [Member] \| Doubtful [Member]
Balance, end of period		6
Commercial Portfolio Segment [Member] \| Commercial Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member]
Balance, end of period	150,378	148,563
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member] \| Pass [Member]
Balance, end of period	148,218	147,788
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member] \| Special Mention [Member]
Balance, end of period	104
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member] \| Substandard [Member]
Balance, end of period	2,033	775
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member] \| Doubtful [Member]
Balance, end of period
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period	23
Commercial Portfolio Segment [Member] \| Acquired Loans [Member]
Balance, end of period	85,135	165,106
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Pass [Member]
Balance, end of period	76,619	154,549
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Special Mention [Member]
Balance, end of period	1,999	332
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Substandard [Member]
Balance, end of period	6,511	8,211
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Doubtful [Member]
Balance, end of period	6	2,014
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Commercial Loans [Member]
Balance, end of period	81,837	154,533
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Commercial Loans [Member] \| Pass [Member]
Balance, end of period	73,609	144,239
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Commercial Loans [Member] \| Special Mention [Member]
Balance, end of period	1,965	332
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Commercial Loans [Member] \| Substandard [Member]
Balance, end of period	6,257	7,948
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Commercial Loans [Member] \| Doubtful [Member]
Balance, end of period	6	2,014
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Commercial Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Agricultural Loans [Member]
Balance, end of period	3,298	10,573
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Agricultural Loans [Member] \| Pass [Member]
Balance, end of period	3,010	10,310
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Agricultural Loans [Member] \| Special Mention [Member]
Balance, end of period	34
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Agricultural Loans [Member] \| Substandard [Member]
Balance, end of period	254	263
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Agricultural Loans [Member] \| Doubtful [Member]
Balance, end of period
Commercial Portfolio Segment [Member] \| Acquired Loans [Member] \| Agricultural Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Balance, end of period

Note 5 - Loans Acquired - Summary of Acquired Loans, Excluding Loans Covered by Loss Share (Details) - USD ($)
$ in Thousands

Dec. 31, 2016

Dec. 31, 2015

Balance, end of period

$ 5,632,890

$ 4,919,355

Pass [Member]

Balance, end of period

5,433,036

4,745,322

Special Mention [Member]

Balance, end of period