Loans and Allowance for Credit Losses - Summary of the Company's Loan participations (Detail) - Loan Participations and Assignments - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 1,768,810	$ 1,542,358
Non-performing Loan Rate (%)	0.43%	0.55%
Gross Charge-offs	$ 0	$ 3
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 1,209,736	$ 1,024,131
Non-performing Loan Rate (%)	0.63%	0.83%
Gross Charge-offs	$ 0	$ 0
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 410,480	$ 422,042
Non-performing Loan Rate (%)	0.00%	0.00%
Gross Charge-offs	$ 0	$ 0
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 148,472	$ 96,134
Non-performing Loan Rate (%)	0.00%	0.00%
Gross Charge-offs	$ 0	$ 0
Business banking | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 122	$ 51
Non-performing Loan Rate (%)	0.00%	0.00%
Gross Charge-offs	$ 0	$ 3