Note 8 - Commitments and Off-balance Sheet Risk - Exposure to Credit Losses (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Unused lines of Credit [Member] | Commercial Portfolio Segment [Member]
Contractual amounts of financial instruments with off-balance sheet risk	$ 537,850,000	$ 522,658,000
Unused lines of Credit [Member] | One to Four Family Mortgages [Member]
Contractual amounts of financial instruments with off-balance sheet risk	59,137,000	61,905,000
Unused lines of Credit [Member] | Consumer Portfolio Segment [Member]
Contractual amounts of financial instruments with off-balance sheet risk	19,360,000	15,612,000
Unused lines of Credit [Member] | Consumer Other Financing Receivable 1 [Member]
Contractual amounts of financial instruments with off-balance sheet risk	6,799,000	8,583,000
Loan Origination Commitments [Member]
Contractual amounts of financial instruments with off-balance sheet risk	119,339,000	178,034,000
Standby Letters of Credit [Member]
Contractual amounts of financial instruments with off-balance sheet risk	24,871,000	34,946,000
Contractual amounts of financial instruments with off-balance sheet risk	$ 767,356,000	$ 821,738,000