LOANS (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred fees	$ 0	$ 9,143
Allowance for credit losses	139,073	47,576	$ 46,321
Net loans and leases	8,411,689	8,424,464
Reverse mortgage, fair value	15,800	16,600	16,200
Loans and Leases Receivable, Nonperforming, Accrual of Interest	32,800	31,500
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	971,541	1,016,500
Allowance for credit losses	11,593	1,381	1,401
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,118,286	1,128,731
Allowance for credit losses	20,370	7,387	8,232
Financing Receivable Portfolio Segment, Including Reverse Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	8,550,762	8,481,183
Commercial and industrial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,096,619	2,046,798
Allowance for credit losses	65,771	22,849	21,016
Owner-occupied commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,313,193	1,296,466
Allowance for credit losses	9,541	4,616	4,949
Commercial mortgages | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,223,117	2,222,976
Allowance for credit losses	26,600	7,452	6,679
Construction | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	626,253	581,082
Allowance for credit losses	5,198	3,891	$ 4,044
Commercial small business leases | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 201,753	$ 188,630