Note 7 - Loans Receivable and Allowance for Loan Losses - Balance of Allowance for Loan Losses by Portfolio Segment (Details) - USD ($)		12 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Recoveries		$ 50,374	$ 464,638
Provision for loan losses		3,395,006	440,000
Ending balance		2,194,815	1,702,365
Ending balance, loans		338,999,832	222,767,212
Beginning balance		1,702,365	1,690,236
Charge-offs		(2,952,930)	(892,509)
Legacy Loans [Member]
Individually evaluated for impairment, allowance		284,177	59,571
Collectively evaluated for impairment, allowance		1,909,456	1,642,794
Individually evaluated for impairment, loans		4,091,563	5,974,073
Collectively evaluated for impairment, loans		205,805,983	166,948,623
Ending balance, loans	[1]	209,897,546	172,922,696
Acquired Loans [Member]
Individually evaluated for impairment, allowance		1,182
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans		1,565,485	1,464,033
Collectively evaluated for impairment, loans		127,536,801	48,380,483
Ending balance, loans		129,102,286	49,844,516
Real Estate Loans [Member]
Ending balance, loans		293,721,660	183,801,748
Real Estate Loans [Member] | Legacy Loans [Member]
Ending balance, loans	[1]	174,842,452	139,853,364
Real Estate Loans [Member] | Acquired Loans [Member]
Ending balance, loans		118,879,208	43,948,384
Real Estate Loans [Member] | Residential [Member]
Recoveries			848
Provision for loan losses		328,222	8,982
Ending balance		553,539	259,895
Beginning balance		259,895	319,565
Charge-offs		(34,578)	(69,500)
Real Estate Loans [Member] | Residential [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance		284,177	59,571
Collectively evaluated for impairment, allowance		269,362	200,324
Individually evaluated for impairment, loans		1,762,417	1,891,602
Collectively evaluated for impairment, loans		71,790,336	48,676,296
Ending balance, loans		73,552,753	50,567,898
Real Estate Loans [Member] | Residential [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans		1,133,646	412,934
Collectively evaluated for impairment, loans		82,758,743	23,589,075
Ending balance, loans		83,892,389	24,002,009
Real Estate Loans [Member] | Investor Loans [Member]
Recoveries		11,599	24,835
Provision for loan losses		1,656,982	251,530
Ending balance		35,275	168,132
Beginning balance		168,132	114,005
Charge-offs		(1,801,438)	(222,238)
Real Estate Loans [Member] | Investor Loans [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance		34,093	168,132
Individually evaluated for impairment, loans		16,919	26,925
Collectively evaluated for impairment, loans		6,725,550	12,049,986
Ending balance, loans		6,742,469	12,076,911
Real Estate Loans [Member] | Investor Loans [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance		1,182
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans		186,888	797,372
Collectively evaluated for impairment, loans		18,592,756	14,985,636
Ending balance, loans		18,779,644	15,783,008
Real Estate Loans [Member] | Commercial [Member]
Recoveries
Provision for loan losses		1,585,446	883,852
Ending balance		1,375,894	901,768
Ending balance, loans		107,564,212	78,115,203
Beginning balance		901,768	585,817
Charge-offs		(1,111,320)	(567,901)
Real Estate Loans [Member] | Commercial [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance		1,375,894	901,768
Individually evaluated for impairment, loans		1,546,812	2,717,144
Collectively evaluated for impairment, loans		91,118,877	72,508,840
Ending balance, loans	[1]	92,665,689	75,225,984
Real Estate Loans [Member] | Commercial [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans		204,844	211,239
Collectively evaluated for impairment, loans		14,693,679	2,677,980
Ending balance, loans		14,898,523	2,889,219
Real Estate Loans [Member] | Commercial construction [Member]
Recoveries			236,904
Provision for loan losses		(33,346)	(262,362)
Ending balance		9,031	42,377
Ending balance, loans		3,190,193	3,256,719
Beginning balance		42,377	67,835
Charge-offs
Real Estate Loans [Member] | Commercial construction [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance		9,031	42,377
Individually evaluated for impairment, loans
Collectively evaluated for impairment, loans		1,881,541	1,982,571
Ending balance, loans	[1]	1,881,541	1,982,571
Real Estate Loans [Member] | Commercial construction [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans
Collectively evaluated for impairment, loans		1,308,652	1,274,148
Ending balance, loans		1,308,652	1,274,148
Commercial Portfolio Segment [Member]
Recoveries		29,257	192,336
Provision for loan losses		(106,474)	(456,908)
Ending balance		149,461	228,199
Ending balance, loans		21,537,366	20,395,592
Beginning balance		228,199	503,304
Charge-offs		(1,521)	(10,533)
Commercial Portfolio Segment [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance		149,461	228,199
Individually evaluated for impairment, loans		753,375	1,279,233
Collectively evaluated for impairment, loans		18,764,654	16,494,734
Ending balance, loans	[1]	19,518,029	17,773,967
Commercial Portfolio Segment [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans
Collectively evaluated for impairment, loans		2,019,337	2,621,625
Ending balance, loans		2,019,337	2,621,625
Home equity loans [Member]
Recoveries
Provision for loan losses		(11,941)	(10,971)
Ending balance		70,071	82,012
Ending balance, loans		20,544,370	14,390,761
Beginning balance		82,012	98,983
Charge-offs			(6,000)
Home equity loans [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance		70,071	82,012
Individually evaluated for impairment, loans		12,040	59,169
Collectively evaluated for impairment, loans		13,266,189	12,163,519
Ending balance, loans	[1]	13,278,229	12,222,688
Home equity loans [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans
Collectively evaluated for impairment, loans		7,266,141	2,168,073
Ending balance, loans		7,266,141	2,168,073
Consumer Portfolio Segment [Member]
Recoveries		9,518	9,715
Provision for loan losses		(23,883)	25,877
Ending balance		1,544	19,982
Ending balance, loans		3,196,436	4,179,111
Beginning balance		19,982	727
Charge-offs		(4,073)	(16,337)
Consumer Portfolio Segment [Member] | Legacy Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance		1,544	19,982
Individually evaluated for impairment, loans
Collectively evaluated for impairment, loans		2,258,836	3,072,677
Ending balance, loans	[1]	2,258,836	3,072,677
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Individually evaluated for impairment, allowance
Collectively evaluated for impairment, allowance
Individually evaluated for impairment, loans		40,107	42,488
Collectively evaluated for impairment, loans		897,493	1,063,946
Ending balance, loans		$ 937,600	$ 1,106,434

[1] As a result of the acquisition of Fraternity Community Bancorp, Inc., the parent company of Fraternity Federal Savings and Loan, in May 2016 and Fairmount Bancorp, Inc., the parent company of Fairmount Bank, in September 2015, we have segmented the portfolio into two components, loans originated by Hamilton Bank "Legacy" and loans acquired from Fraternity Community Bancorp, Inc. and Fairmount Bancorp, Inc. "Acquired".