Investment Securities (Summary of Debt Securities Held-to-Maturity) (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	$ 6,564,879	$ 6,198,339
Interest Receivable	226,300	50,700
Agency CMO
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	28,358	42,405
Agency MBS
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	2,626,114	2,901,593
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	2,831,949	2,378,475
Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	928,845	705,918
CMBS
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	149,613	169,948
Moody's, Aaa Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	485,648	377,374
Moody's, Aaa Rating [Member] | Agency CMO
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	0	0
Moody's, Aaa Rating [Member] | Agency MBS
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	0	0
Moody's, Aaa Rating [Member] | Agency commercial mortgage-backed securities (agency CMBS) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	0	0
Moody's, Aaa Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	336,035	207,426
Moody's, Aaa Rating [Member] | CMBS
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	149,613	169,948
Moody's, Aa1 Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	5,649,733	5,442,277
Moody's, Aa1 Rating [Member] | Agency CMO
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	28,358	42,405
Moody's, Aa1 Rating [Member] | Agency MBS
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	2,626,114	2,901,593
Moody's, Aa1 Rating [Member] | Agency commercial mortgage-backed securities (agency CMBS) [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	2,831,949	2,378,475
Moody's, Aa1 Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	163,312	119,804
Moody's, Aa1 Rating [Member] | CMBS
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	0	0
Moody's, Aa2 Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	255,235	227,106
Moody's, Aa2 Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	255,235	227,106
Moody's, Aa3 Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	116,870	104,232
Moody's, Aa3 Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	116,870	104,232
Moody's, A1 Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	38,177	35,878
Moody's, A1 Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	38,177	35,878
Moody's, A2 Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	4,165	8,260
Moody's, A2 Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	4,165	8,260
Moody's, Baa2 Rating [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	0	95
Moody's, Baa2 Rating [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	0	95
Moody's, Not Rated [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	15,051	3,117
Moody's, Not Rated [Member] | Municipal Bonds [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Held to maturity securities	$ 15,051	$ 3,117