Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020	Jan. 04, 2019
Income Tax Disclosure [Line Items]
Adjustment to net deferred tax asset for change in NJ tax law	$ 0	$ 0	$ 943,000
Statutory federal rate	21.00%	21.00%
Net deferred tax assets	$ 19,278,000	$ 14,805,000
Unrecognized tax benefits	0	0
Unrecognized tax benefits, income tax penalties and interest expense	$ 0	$ 0
Accounting Standards Update 2016-13
Income Tax Disclosure [Line Items]
Net deferred tax assets				$ 1,400,000
Highlands Bancorp, Inc.
Income Tax Disclosure [Line Items]
Net deferred tax assets					$ 4,300,000