Note 5 - Loans Acquired (Details) - Summary of Acquired Loans, Excluding Loans Covered by Loss Share (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Consumer:
Acquired loans	$ 2,736,634	$ 2,404,935
Other Consumer [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	8,479
Other Consumer [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	32
Other Consumer [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	8,511
Total Consumer Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	8,479
Total Consumer Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	32
Total Consumer Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	8,511
Construction Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	27,430
Construction Loans [Member] | Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	78
Construction Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	9,339
Construction Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	36,847
Single Family Residential Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	135,240
Single Family Residential Loans [Member] | Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	683
Single Family Residential Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	7,311
Single Family Residential Loans [Member] | Acquired Loans [Member] | Risk Rate 7 [Member]
Consumer:
Acquired loans	1,854
Single Family Residential Loans [Member] | Acquired Loans [Member] | Risk Rate 8 [Member]
Consumer:
Acquired loans	5
Single Family Residential Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	145,093
Other Commercial Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	317,965
Other Commercial Loans [Member] | Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	605
Other Commercial Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	15,598
Other Commercial Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	334,168
Total Real Estate Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	480,635
Total Real Estate Loans [Member] | Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	1,366
Total Real Estate Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	32,248
Total Real Estate Loans [Member] | Acquired Loans [Member] | Risk Rate 7 [Member]
Consumer:
Acquired loans	1,854
Total Real Estate Loans [Member] | Acquired Loans [Member] | Risk Rate 8 [Member]
Consumer:
Acquired loans	5
Total Real Estate Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	516,108
Commercial [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	43,585
Commercial [Member] | Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	69
Commercial [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	3,607
Commercial [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	47,261
Agricultural Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	3,030
Agricultural Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	1,070
Agricultural Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	4,100
Total Commercial Loans [Member] | Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	46,615
Total Commercial Loans [Member] | Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	69
Total Commercial Loans [Member] | Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	4,677
Total Commercial Loans [Member] | Acquired Loans [Member]
Consumer:
Acquired loans	51,361
Acquired Loans [Member] | Risk Rate 1-4 [Member]
Consumer:
Acquired loans	535,729
Acquired Loans [Member] | Risk Rate 5 [Member]
Consumer:
Acquired loans	1,435
Acquired Loans [Member] | Risk Rate 6 [Member]
Consumer:
Acquired loans	36,957
Acquired Loans [Member] | Risk Rate 7 [Member]
Consumer:
Acquired loans	1,854
Acquired Loans [Member] | Risk Rate 8 [Member]
Consumer:
Acquired loans	5
Acquired Loans [Member]
Consumer:
Acquired loans	575,980
Risk Rate 1-4 [Member]
Consumer:
Acquired loans	2,642,549	2,301,188
Risk Rate 5 [Member]
Consumer:
Acquired loans	11,938	9,282
Risk Rate 6 [Member]
Consumer:
Acquired loans	80,152	94,382
Risk Rate 7 [Member]
Consumer:
Acquired loans	1,990	66
Risk Rate 8 [Member]
Consumer:
Acquired loans	$ 5	$ 17