Note 7 - Loans Receivable and Allowance for Loan Losses - Loans by Risk Grade (Details) - USD ($)		Mar. 31, 2018	Mar. 31, 2017
Loans		$ 389,221,239	$ 338,999,832
Legacy Loans [Member]
Loans	[1]	277,250,109	209,897,546
Acquired Loans [Member]
Loans		111,971,130	129,102,286
Pass [Member]
Loans		375,484,442	324,151,352
Pass [Member] | Legacy Loans [Member]
Loans		266,444,555	200,026,200
Pass [Member] | Acquired Loans [Member]
Loans		109,039,887	124,125,152
Special Mention [Member]
Loans		7,022,190	11,401,812
Special Mention [Member] | Legacy Loans [Member]
Loans		5,688,785	7,828,565
Special Mention [Member] | Acquired Loans [Member]
Loans		1,333,405	3,573,247
Substandard [Member]
Loans		6,714,607	3,446,668
Substandard [Member] | Legacy Loans [Member]
Loans		5,116,769	2,042,781
Substandard [Member] | Acquired Loans [Member]
Loans		1,597,838	1,403,887
Doubtful [Member]
Loans
Doubtful [Member] | Legacy Loans [Member]
Loans
Doubtful [Member] | Acquired Loans [Member]
Loans
Unlikely to be Collected Financing Receivable [Member]
Loans
Unlikely to be Collected Financing Receivable [Member] | Legacy Loans [Member]
Loans
Unlikely to be Collected Financing Receivable [Member] | Acquired Loans [Member]
Loans
Real Estate Loans [Member]
Loans		309,465,974	293,721,660
Real Estate Loans [Member] | Legacy Loans [Member]
Loans	[1]	206,141,595	174,842,452
Real Estate Loans [Member] | Acquired Loans [Member]
Loans		103,324,379	118,879,208
Real Estate Loans [Member] | Residential [Member] | Legacy Loans [Member]
Loans		90,699,011	73,552,753
Real Estate Loans [Member] | Residential [Member] | Acquired Loans [Member]
Loans		72,749,066	83,892,389
Real Estate Loans [Member] | Residential [Member] | Pass [Member]
Loans		158,765,098	152,949,798
Real Estate Loans [Member] | Residential [Member] | Pass [Member] | Legacy Loans [Member]
Loans		87,863,805	71,721,341
Real Estate Loans [Member] | Residential [Member] | Pass [Member] | Acquired Loans [Member]
Loans		70,901,293	81,228,457
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member]
Loans		3,291,173	3,224,423
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans		2,365,652	1,499,436
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans		925,521	1,724,987
Real Estate Loans [Member] | Residential [Member] | Substandard [Member]
Loans		1,391,806	1,270,921
Real Estate Loans [Member] | Residential [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		469,554	331,976
Real Estate Loans [Member] | Residential [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		922,252	938,945
Real Estate Loans [Member] | Investor Loans [Member] | Legacy Loans [Member]
Loans		9,275,031	6,742,469
Real Estate Loans [Member] | Investor Loans [Member] | Acquired Loans [Member]
Loans		17,460,809	18,779,644
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member]
Loans		25,933,428	24,880,026
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member] | Legacy Loans [Member]
Loans		9,214,082	6,728,493
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member] | Acquired Loans [Member]
Loans		16,719,346	18,151,533
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member]
Loans		297,209	408,803
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans		297,209	408,803
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member]
Loans		505,203	233,284
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		60,949	13,976
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		444,254	219,308
Real Estate Loans [Member] | Commercial [Member]
Loans		112,166,254	107,564,212
Real Estate Loans [Member] | Commercial [Member] | Legacy Loans [Member]
Loans	[1]	100,403,769	92,665,689
Real Estate Loans [Member] | Commercial [Member] | Acquired Loans [Member]
Loans		11,762,485	14,898,523
Real Estate Loans [Member] | Commercial [Member] | Pass [Member]
Loans		104,518,917	98,177,735
Real Estate Loans [Member] | Commercial [Member] | Pass [Member] | Legacy Loans [Member]
Loans		92,955,370	84,789,748
Real Estate Loans [Member] | Commercial [Member] | Pass [Member] | Acquired Loans [Member]
Loans		11,563,547	13,387,987
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member]
Loans		3,092,135	7,634,821
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans		3,092,135	6,329,129
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans			1,305,692
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member]
Loans		4,555,202	1,751,656
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		4,356,264	1,546,812
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		198,938	204,844
Real Estate Loans [Member] | Commercial construction [Member]
Loans		7,115,803	3,190,193
Real Estate Loans [Member] | Commercial construction [Member] | Legacy Loans [Member]
Loans	[1]	5,763,784	1,881,541
Real Estate Loans [Member] | Commercial construction [Member] | Acquired Loans [Member]
Loans		1,352,019	1,308,652
Real Estate Loans [Member] | Commercial construction [Member] | Pass [Member]
Loans		7,115,803	3,190,193
Real Estate Loans [Member] | Commercial construction [Member] | Pass [Member] | Legacy Loans [Member]
Loans		5,763,784	1,881,541
Real Estate Loans [Member] | Commercial construction [Member] | Pass [Member] | Acquired Loans [Member]
Loans		1,352,019	1,308,652
Real Estate Loans [Member] | Commercial construction [Member] | Special Mention [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Substandard [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Substandard [Member] | Legacy Loans [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Substandard [Member] | Acquired Loans [Member]
Loans
Commercial Portfolio Segment [Member]
Loans	[2]	40,143,965	21,537,366
Commercial Portfolio Segment [Member] | Legacy Loans [Member]
Loans	[1],[2]	38,302,739	19,518,029
Commercial Portfolio Segment [Member] | Acquired Loans [Member]
Loans	[2]	1,841,226	2,019,337
Commercial Portfolio Segment [Member] | Pass [Member]
Loans		39,819,519	21,396,100
Commercial Portfolio Segment [Member] | Pass [Member] | Legacy Loans [Member]
Loans		37,978,293	19,376,763
Commercial Portfolio Segment [Member] | Pass [Member] | Acquired Loans [Member]
Loans		1,841,226	2,019,337
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans		134,524
Commercial Portfolio Segment [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans		134,524
Commercial Portfolio Segment [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans		189,922	141,266
Commercial Portfolio Segment [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		189,922	141,266
Commercial Portfolio Segment [Member] | Substandard [Member] | Acquired Loans [Member]
Loans
Home equity loans [Member]
Loans		19,995,789	20,544,370
Home equity loans [Member] | Legacy Loans [Member]
Loans	[1]	13,956,327	13,278,229
Home equity loans [Member] | Acquired Loans [Member]
Loans		6,039,462	7,266,141
Home equity loans [Member] | Pass [Member]
Loans		19,864,519	20,402,642
Home equity loans [Member] | Pass [Member] | Legacy Loans [Member]
Loans		13,935,732	13,269,478
Home equity loans [Member] | Pass [Member] | Acquired Loans [Member]
Loans		5,928,787	7,133,164
Home equity loans [Member] | Special Mention [Member]
Loans		110,675	132,977
Home equity loans [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Home equity loans [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans		110,675	132,977
Home equity loans [Member] | Substandard [Member]
Loans		20,595	8,751
Home equity loans [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		20,595	8,751
Home equity loans [Member] | Substandard [Member] | Acquired Loans [Member]
Loans
Consumer Portfolio Segment [Member]
Loans	[3]	19,615,511	3,196,436
Consumer Portfolio Segment [Member] | Legacy Loans [Member]
Loans	[1],[3]	18,849,448	2,258,836
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Loans	[3]	766,063	937,600
Consumer Portfolio Segment [Member] | Pass [Member]
Loans		19,467,158	3,154,858
Consumer Portfolio Segment [Member] | Pass [Member] | Legacy Loans [Member]
Loans		18,733,489	2,258,836
Consumer Portfolio Segment [Member] | Pass [Member] | Acquired Loans [Member]
Loans		733,669	896,022
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans		96,474	788
Consumer Portfolio Segment [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans		96,474
Consumer Portfolio Segment [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans			788
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans		51,879	40,790
Consumer Portfolio Segment [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		19,485
Consumer Portfolio Segment [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		$ 32,394	$ 40,790

[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".

[2] "Legacy" commercial business loans at March 31, 2018 includes a $15.5 million pool of commercial lease loans purchased in June 2017 and $3.2 million in guaranteed SBA purchased loans.

[3] "Legacy" consumer loans at March 31, 2018 includes $19.9 million of purchased loan pools consisting of recreational vehicles that were purchased in August and December 2017.