Earnings per share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 921,630	$ 36,102	$ 2,058,493	$ 344,494
Weighted average common shares outstanding	5,820,342	2,965,783	5,813,915	2,965,783
Effect of dilutive stock options (in shares)	311,478	327,496	304,615	327,516
Diluted shares	6,131,820	3,293,279	6,118,530	3,293,299
Basic earnings per common share (in dollars per share)	$ 0.16	$ 0.01	$ 0.35	$ 0.12
Diluted earnings per common share (in dollars per share)	$ 0.15	$ 0.01	$ 0.34	$ 0.10