Fair Value Disclosures of Financial Assets and Liabilities - Book Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial assets:
Investment securities, held to maturity, net	$ 90,646	$ 111,747
Stock in FHLB of Pittsburgh	6,073	5,771
Accrued interest receivable	41,596	44,335
Financial liabilities:
Deposits	13,240,062	11,856,664
Accrued interest payable	736	1,450
Book Value | Level 1
Financial assets:
Cash, cash equivalents and restricted cash	1,532,939	1,654,735
Book Value | Level 2
Financial assets:
Investment securities, available for sale	5,205,311	2,529,057
Investment securities, held to maturity, net	90,642	111,741
Loans, held for sale	113,349	197,541
Stock in FHLB of Pittsburgh	6,073	5,771
Accrued interest receivable	41,596	44,335
Other assets	5,153	14,448
Financial liabilities:
Deposits	13,240,062	11,856,664
Borrowed funds	239,477	340,641
Accrued interest payable	736	1,450
Book Value | Level 3
Financial assets:
Other investments	10,518	9,541
Loans and leases, net	7,791,482	8,795,935
Financial liabilities:
Standby letters of credit	674	630
Book Value | Levels 2, 3
Financial liabilities:
Other liabilities	23,291	32,257
Fair Value | Level 1
Financial assets:
Cash, cash equivalents and restricted cash	1,532,939	1,654,735
Fair Value | Level 2
Financial assets:
Investment securities, available for sale	5,205,311	2,529,057
Investment securities, held to maturity, net	94,131	116,421
Loans, held for sale	113,349	197,541
Stock in FHLB of Pittsburgh	6,073	5,771
Accrued interest receivable	41,596	44,335
Other assets	5,153	14,448
Financial liabilities:
Deposits	13,236,816	11,868,897
Borrowed funds	225,119	340,106
Accrued interest payable	736	1,450
Fair Value | Level 3
Financial assets:
Other investments	10,518	9,541
Loans and leases, net	7,723,867	9,130,003
Financial liabilities:
Standby letters of credit	674	630
Fair Value | Levels 2, 3
Financial liabilities:
Other liabilities	$ 23,291	$ 32,257