Note 5 - Loans Acquired (Details) - Summary of the Non-covered Impaired Loans Acquired in Acquisitions - Loans Acquired, Not Covered By FDIC Loss Share [Member] $ in Thousands	Feb. 27, 2015 USD ($)
Liberty [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required principal and interest at acquisition	$ 774,777
Cash flows expected to be collected at acquisition	774,777
Accretable yield	(4,869)
Basis in acquired loans at acquisition	769,908
Liberty [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required principal and interest at acquisition	15,716
Non-accretable difference (expected losses and foregone interest)	(4,978)
Cash flows expected to be collected at acquisition	10,738
Accretable yield	12
Basis in acquired loans at acquisition	10,750
Community First Bancshares, Inc. [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required principal and interest at acquisition	1,153,255
Cash flows expected to be collected at acquisition	1,153,255
Accretable yield	(23,712)
Basis in acquired loans at acquisition	1,129,543
Community First Bancshares, Inc. [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required principal and interest at acquisition	10,143
Non-accretable difference (expected losses and foregone interest)	(3,247)
Cash flows expected to be collected at acquisition	6,896
Accretable yield	104
Basis in acquired loans at acquisition	$ 7,000