BANK PREMISES AND EQUIPMENT (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total cost	$ 307,134,000	$ 216,476,000
Accumulated depreciation	(111,544,000)	(100,083,000)
Net bank premises and equipment	195,590,000	116,393,000
Depreciation expense	12,500,000	12,800,000	$ 11,400,000
Rental Income, Nonoperating	890,000	1,500,000
Land [Member]
Property, Plant and Equipment [Line Items]
Total cost	54,295,000	32,450,000
Bank Premises [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 96,887,000	63,544,000
Bank Premises [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Bank Premises [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 45,263,000	38,667,000
Leasehold Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	1 year
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	27 years
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 89,029,000	$ 81,815,000
Furniture and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Furniture and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	12 years
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 21,660,000			$ 10,600,000
Machinery and Equipment | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years