Note 4 - Loans and Allowance for Loan Losses (Details) - Retail Credit Risk by Collateral Type (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Total retail	$ 2,089,277,000	$ 1,053,243,000	$ 1,041,189,000
Originated Loan [Member] | Retail Home Equity and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	50,059,000	35,080,000
Originated Loan [Member] | Retail 1-4 Family Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	42,868,000	31,467,000
Originated Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	1,246,116,000	1,053,243,000
Acquired Loan [Member] | Retail Home Equity and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	109,219,000	0
Acquired Loan [Member] | Retail 1-4 Family Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	171,828,000	0
Acquired Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	843,161,000	0
Retail Home Equity and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	159,278,000	35,080,000
Retail 1-4 Family Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	$ 214,696,000	$ 31,467,000