INVESTMENT SECURITIES (Schedule of Other Investments) (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
FHLB of Pittsburgh and FRB stock	$ 659,146,000	$ 716,615,000
LIHTC investments	285,932,000	265,271,000
Equity securities not held for trading	13,221,000	12,697,000
Interest-bearing deposits with an affiliate bank	750,000,000	0
Trading securities	19,766,000	1,097,000
Total	1,728,065,000	995,680,000
Off-balance Securitization Trusts
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Equity securities not held for trading	$ 200,000	$ 0