Note 9 - Allowance for Loan Losses and Credit Quality Information - Purchased Loans Acquired Through Acquisition (Details)	3 Months Ended
	Jun. 30, 2017 USD ($)
Carrying Amount	$ 300,000
Purchased Performing Loans [Member]
Contractual Principle Receivable	15,363,000
Contractual Principle Receivable, change due to payments/refinances	(2,087,000)
Contractual Principle Receivable, transferred to foreclosed assets	(2,000)
Contractual Principle Receivable, change due to loan charge-off	(7,000)
Contractual Principle Receivable	13,267,000
Accretable Difference	(307,000)
Accretable Difference, change due to payments/refinances	32,000
Accretable Difference, transferred to foreclosed assets	0
Accretable Difference, change due to loan charge-off	0
Accretable Difference	(275,000)
Carrying Amount	15,056,000
Carrying Amount, change due to payments/refinances	(2,055,000)
Carrying Amount, transferred to foreclosed assets	(2,000)
Carrying Amount, Change due to loan charge-off	(7,000)
Carrying Amount	12,992,000
Purchased Credit Impaired Loans [Member]
Contractual Principle Receivable	392,000
Contractual Principle Receivable, change due to payments/refinances	(6,000)
Contractual Principle Receivable	386,000
Carrying Amount	344,000
Carrying Amount, change due to payments/refinances	(3,000)
Carrying Amount	341,000
Non-accretable Difference	(45,000)
Non-accretable Difference, change due to payments/refinances	3,000
Non-accretable Difference	$ (48,000)