FAIR VALUE DISCLOSURES OF FINANCIAL ASSETS AND LIABILITIES - Book Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financial assets:
Investment securities, held to maturity, net	$ 1,111,629	$ 90,646
Stock in FHLB of Pittsburgh	24,116	6,073
Accrued interest receivable	74,448	41,596
Financial liabilities:
Deposits	16,203,569	13,240,062
Accrued interest payable	5,174	736
Book Value | Level 1
Financial assets:
Cash, cash equivalents and restricted cash	837,258	1,532,939
Book Value | Level 2
Financial assets:
Investment securities, available for sale	4,093,060	5,205,311
Investment securities, held to maturity, net	1,111,619	90,642
Loans, held for sale	42,985	113,349
Stock in FHLB of Pittsburgh	24,116	6,073
Accrued interest receivable	74,448	41,596
Financial liabilities:
Deposits	16,203,569	13,240,062
Borrowed funds	726,894	239,477
Accrued interest payable	5,174	736
Book Value | Level 3
Financial assets:
Other investments	26,120	10,518
Loans and leases, net	11,759,992	7,791,482
Financial liabilities:
Standby letters of credit	739	674
Book Value | Levels 2, 3
Financial assets:
Other assets	156,993	5,153
Financial liabilities:
Other liabilities	173,622	23,291
Fair Value | Level 1
Financial assets:
Cash, cash equivalents and restricted cash	837,258	1,532,939
Fair Value | Level 2
Financial assets:
Investment securities, available for sale	4,093,060	5,205,311
Investment securities, held to maturity, net	1,040,104	94,131
Loans, held for sale	42,985	113,349
Stock in FHLB of Pittsburgh	24,116	6,073
Accrued interest receivable	74,448	41,596
Financial liabilities:
Deposits	16,156,124	13,236,816
Borrowed funds	709,014	225,119
Accrued interest payable	5,174	736
Fair Value | Level 3
Financial assets:
Other investments	26,120	10,518
Loans and leases, net	11,567,888	7,723,867
Financial liabilities:
Standby letters of credit	739	674
Fair Value | Levels 2, 3
Financial assets:
Other assets	156,993	5,153
Financial liabilities:
Other liabilities	$ 173,622	$ 23,291