Loans, Allowance for Credit Losses and Credit Quality - Textual (Details) - USD ($)		6 Months Ended
		Jun. 30, 2023		Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	[1]	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses		$ 140,647,000	[1]	$ 159,131,000	$ 152,419,000	$ 144,319,000		$ 144,518,000	$ 146,922,000
Unfunded commitments		$ 1,500,000			1,300,000
Days to be termed as non accrual loans		90 days
Additional commitments to lend to borrowers experiencing financial difficulty party to a loan modification		$ 0
Additional commitments to lend to borrowers party to a TDR					64,000
Financing Receivable, Nonaccrual	[2]	45,702,000			54,881,000
Financial Asset, Not Past Due | Aging Loan Modification Member
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans and Leases Receivable, Net of Deferred Income		32,692,000
Financing Receivable, Nonaccrual		19,600,000
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses		15,142,000	[1]	$ 36,932,000	27,559,000	$ 14,107,000		$ 14,169,000	$ 14,402,000
Financing Receivable, Nonaccrual		3,235,000			$ 26,693,000
Commercial And Industrial [Member] | Financial Asset, Not Past Due | Aging Loan Modification Member
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 12,963,000

[1] Balances of accrued interest receivable excluded from amortized cost and the calculation of allowance for credit losses amounted to $54.0 million and $39.0 million as of June 30, 2023 and June 30, 2022, respectively.

[2] included $11.5 million of nonaccruing troubled debt restructures ("TDRs").