Loans and Allowance for Loan Losses - Summary of Internal Risk-Rating Categories (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 12,903,954	$ 12,281,510
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	3,023,729	2,960,527
Commercial Portfolio Segment | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,985,654	4,522,513
Commercial Portfolio Segment | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	314,193	222,328
Commercial Portfolio Segment | Business banking
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 1,096,436	1,334,694
Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		9,040,062
Nonperforming Loans | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		872,544
Nonperforming Loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		7,640,376
Nonperforming Loans | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		226,632
Nonperforming Loans | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		288,663
Nonperforming Loans | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		11,847
Nonperforming Loans | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		2,960,527
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		171,537
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		2,656,873
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		70,141
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		50,339
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		11,637
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		4,522,513
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		4,378
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		4,199,803
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		104,517
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		213,815
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		222,328
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		213,744
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		1,889
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		6,695
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Business banking
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		1,334,694
Nonperforming Loans | Commercial Portfolio Segment | Business banking | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		696,629
Nonperforming Loans | Commercial Portfolio Segment | Business banking | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		569,956
Nonperforming Loans | Commercial Portfolio Segment | Business banking | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		50,085
Nonperforming Loans | Commercial Portfolio Segment | Business banking | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		17,814
Nonperforming Loans | Commercial Portfolio Segment | Business banking | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		210
Nonperforming Loans | Commercial Portfolio Segment | Business banking | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		$ 0