Note 9 - Borrowings - Outstanding Advances (Details) (Parentheticals) - Federal Home Loan Bank of Chicago [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Interest rate, fixed	1.46%
Matures 02/15/2018 at 1.27% [Member]
Interest rate, fixed	1.27%
Maturity date on fixed rate advance	Feb. 15, 2018
Matures 03/30/2018 at 1.72% [Member]
Interest rate, fixed	1.72%	1.72%
Maturity date on fixed rate advance	Mar. 30, 2018	Mar. 30, 2018
Matures 05/15/2018 at 1.34% [Member]
Interest rate, fixed	1.34%
Maturity date on fixed rate advance	May 15, 2018
Matures 08/30/2019 at 1.56% [Member]
Interest rate, fixed	1.56%
Maturity date on fixed rate advance	Aug. 30, 2018
Matures 09/25/2018 at 1.46% [Member]
Interest rate, fixed	1.46%
Maturity date on fixed rate advance	Sep. 25, 2018
Matures 04/01/2019 at 2.00% [Member]
Interest rate, fixed	2.00%	2.00%
Maturity date on fixed rate advance	Apr. 01, 2019	Apr. 01, 2019
Matures 12/16/2019 at 2.08% [Member]
Interest rate, fixed	2.08%
Maturity date on fixed rate advance	Dec. 16, 2019
Matures 10/03/2022 at 1.48% [Member]
Interest rate, fixed	1.48%	1.48%
Maturity date on fixed rate advance	Oct. 03, 2022	Oct. 03, 2022