Note 9 - Short-term Borrowings (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Short-term Debt [Table Text Block]

	2017		2016
Overnight repurchase agreements with customers	$	7,003,122	$	8,131,387
Federal funds purchased		6,990,000		31,840,000
	$	13,993,122	$	39,971,387

Schedule of Repurchase Agreements [Table Text Block]

	2017			2016
Average daily balance during the period	$	7,475,824		$	30,082,866
Average daily interest rate during the period		0.08	%		0.07	%
Maximum month-end balance during the period	$	11,829,201		$	59,833,229
Weighted average rate as of end of period		0.15	%		0.02	%

	2017			2016
Average daily balance during the period	$	13,486,239		$	19,105,595
Average daily interest rate during the period		1.31	%		0.56	%
Maximum month-end balance during the period	$	33,650,000		$	51,750,000
Weighted average rate as of end of period		1.24	%		0.70	%

Securities Sold under Agreements to Repurchase [Member]

Notes Tables

Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets [Table Text Block]

	2017		2016
U.S. govt. sponsored agency securities	$	2,077,702	$	630,077
Residential mortgage-backed and related securities		18,816,280		19,090,261
Total securities pledged to overnight customer repurchase agreements		20,893,982		19,720,338
Less: overcollateralized position		13,890,860		11,588,951
	$	7,003,122	$	8,131,387