Note 3 - Loans and Allowance for Loan Losses - Retail Credit Exposure (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 69,396,000	$ 67,816,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	65,813,000	55,255,000
Originated Loan [Member] | Retail Portfolio Segment [Member]
Loans	135,209,000	123,071,000	$ 107,235,000
Originated Loan [Member]
Loans	1,799,954,000	1,616,587,000	$ 1,429,623,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	61,671,000	72,830,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	123,305,000	135,130,000
Acquired Loan [Member] | Retail Portfolio Segment [Member]
Loans	184,976,000	207,960,000
Acquired Loan [Member]
Loans	579,986,000	661,140,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	131,067,000	140,646,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	189,118,000	190,385,000
Retail Portfolio Segment [Member]
Loans	320,185,000	331,031,000
Loans	$ 2,379,940,000	$ 2,277,727,000