Loans and Allowance for Loan Losses - Summary of Internal Risk-Rating Categories (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 12,281,510	$ 9,730,525	$ 8,987,046
Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	9,040,062	7,213,518
Unrated | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	872,544	1,580,852
Pass | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	7,640,376	5,073,668
Special mention | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	226,632	280,101
Substandard | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	288,663	260,207
Doubtful | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	11,847	18,690
Loss | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	0
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	2,960,527	1,995,016	1,642,184
Commercial and industrial | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	2,960,527	1,995,016
Commercial and industrial | Unrated | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	171,537	655,346
Commercial and industrial | Pass | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	2,656,873	1,199,522
Commercial and industrial | Special mention | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	70,141	78,117
Commercial and industrial | Substandard | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	50,339	47,525
Commercial and industrial | Doubtful | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	11,637	14,506
Commercial and industrial | Loss | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	0
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,522,513	3,573,630	3,535,441
Commercial real estate | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,522,513	3,573,630
Commercial real estate | Unrated | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,378	6,585
Commercial real estate | Pass | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,199,803	3,256,697
Commercial real estate | Special mention | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	104,517	134,562
Commercial real estate | Substandard | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	213,815	173,308
Commercial real estate | Doubtful | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	2,478
Commercial real estate | Loss | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	0
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	222,328	305,708	273,774
Commercial construction | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	222,328	305,708
Commercial construction | Unrated | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	0
Commercial construction | Pass | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	213,744	280,792
Commercial construction | Special mention | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,889	10,330
Commercial construction | Substandard | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	6,695	14,586
Commercial construction | Doubtful | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	0
Commercial construction | Loss | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	0	0
Business Banking | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,334,694	1,339,164	$ 771,498
Business Banking | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,334,694	1,339,164
Business Banking | Unrated | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	696,629	918,921
Business Banking | Pass | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	569,956	336,657
Business Banking | Special mention | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	50,085	57,092
Business Banking | Substandard | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	17,814	24,788
Business Banking | Doubtful | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	210	1,706
Business Banking | Loss | Nonperforming Loans | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 0	$ 0