INCOME TAXES - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Adjustment to the net deferred tax asset for the Tax Cuts and Jobs Act	$ 0	$ 885,000	$ 0
Valuation allowance	$ 0	$ 0
Utilization period of operating loss carryforwards	14 years
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 4,200,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	21,000,000
State net operating loss carried regular operations	2,200,000
Mid-Wisconsin, Baylake, and First Menasha | Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	4,200,000
Mid-Wisconsin, Baylake, and First Menasha | State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 18,800,000