GOODWILL AND OTHER INTANGIBLES - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Sep. 01, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Finite Lived Intangible Assets [Line Items]
Goodwill		$ 34,401	$ 34,401	$ 28,098
Goodwill impairment			0
Intangible assets amount		$ 43,893	43,893	$ 7,573	$ 8,340
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Weighted average amortization period		1 year
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Weighted average amortization period		6 years
Core Deposits [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets amount		$ 37,749	37,749		3,695
Customer Relationships [Member] | Credit Card [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets amount		5,789	5,789		4,137
Customer Relationships [Member] | Insurance Customer Intangible [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets amount		$ 355	$ 355		$ 508
Santander [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill	$ 6,300
Total purchase price consideration (cash)	1,277,626
Intangibles	39,200
Santander [Member] | Core Deposits [Member]
Finite Lived Intangible Assets [Line Items]
Intangibles	35,400
Santander [Member] | Customer Relationships [Member] | Credit Card [Member]
Finite Lived Intangible Assets [Line Items]
Intangibles	$ 3,800