Note 3 - Loans and Allowance for Loan Losses (Details) - Retail Credit Exposure - USD ($)	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Total retail	$ 2,295,668,000	$ 2,277,727,000
Originated Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	1,687,476,000	1,616,587,000	$ 1,328,713,000
Acquired Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	608,192,000	661,140,000
Retail Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	321,218,000	331,031,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	135,683,000	140,646,000
Retail Portfolio Segment [Member] | 1-4 Family Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	185,535,000	190,385,000
Retail Portfolio Segment [Member] | Originated Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	124,699,000	123,071,000	$ 97,872,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	68,342,000	67,816,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | 1-4 Family Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	56,357,000	55,255,000
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	196,519,000	207,960,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	67,341,000	72,830,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | 1-4 Family Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total retail	$ 129,178,000	$ 135,130,000