INCOME TAXES - Deferred Tax Assets And Liabilities (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Allowance for credit losses	$ 42,231,000	$ 14,287,000
Lease liability	19,192,000	19,616,000
Fair value acquisition adjustments	0	1,322,000
Employee benefits	6,108,000	4,535,000
Unrealized losses on pension plan	3,249,000	2,845,000
Deferred loan fees and costs	4,486,000	471,000
Equity based compensation	1,856,000	659,000
Losses on other real estate owned	203,000	201,000
Other than temporary impairment	75,000	76,000
Loan and deposit premium/discount	1,081,000	1,422,000
Reserve for recourse loans	546,000	166,000
Net operating loss carryforward	1,475,000	916,000
Other	181,000	159,000
Gross deferred tax assets	80,683,000	46,675,000
Valuation allowance	(1,479,000)	(880,000)
Net deferred tax asset	79,204,000	45,795,000
Deferred tax liabilities:
Right of use asset	(16,693,000)	(17,688,000)
Unrealized gains on investments available-for-sale	(9,684,000)	(1,379,000)
Pension plan costs	(2,211,000)	(2,373,000)
Depreciation	(2,950,000)	(2,744,000)
Intangible assets	(6,894,000)	(3,338,000)
Bond accretion	(195,000)	(322,000)
Section 481 adjustments	(669,000)	(1,335,000)
Fair value acquisition adjustments	(555,000)	0
Other	(567,000)	(585,000)
Gross deferred tax liabilities	(40,418,000)	(29,764,000)
Net deferred tax asset	$ 38,786,000	$ 16,031,000