Loans and Leases and the Allowance for Credit Losses - Summary of Loan grades applied various classes of Commercial and Real Estate Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	$ 9,545,000		$ 9,545,000		$ 18,423,000
Year two	16,667,000		16,667,000		21,683,000
Year three	19,766,000		19,766,000		15,025,000
Year four	13,567,000		13,567,000		10,555,000
Year five	9,431,000		9,431,000		10,062,000
Prior	33,184,000		33,184,000		27,464,000
Total	135,002,000		135,002,000		134,068,000
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Year one	6,000		7,000
Year two	20,000		35,000
Year three	20,000		41,000
Year four	19,000		32,000
Year five	15,000		24,000
Prior	53,000		88,000
Total	180,000	$ 162,000	343,000	$ 257,000
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	4,305,000		4,305,000		9,010,000
Year two	7,933,000		7,933,000		8,434,000
Year three	7,647,000		7,647,000		5,133,000
Year four	4,500,000		4,500,000		2,465,000
Year five	2,123,000		2,123,000		2,332,000
Prior	7,258,000		7,258,000		5,474,000
Revolving Loans	26,130,000		26,130,000		24,048,000
Revolving Loans Converted to Term Loans	131,000		131,000		114,000
Total	60,027,000		60,027,000		57,010,000
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Year one	1,000		1,000
Year two	7,000		14,000
Year three	10,000		19,000
Year four	11,000		15,000
Year five	7,000		10,000
Prior	9,000		14,000
Revolving Loans	33,000		83,000
Revolving Loans Converted to Term Loans	0		0
Total	78,000		156,000
Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	4,226,000		4,226,000		8,689,000
Year two	7,554,000		7,554,000		8,087,000
Year three	7,107,000		7,107,000		4,800,000
Year four	4,199,000		4,199,000		2,248,000
Year five	1,932,000		1,932,000		2,169,000
Prior	6,299,000		6,299,000		4,843,000
Revolving Loans	24,139,000		24,139,000		22,345,000
Revolving Loans Converted to Term Loans	73,000		73,000		70,000
Total	55,529,000		55,529,000		53,251,000
Commercial and industrial | Criticized accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	74,000		74,000		292,000
Year two	334,000		334,000		279,000
Year three	443,000		443,000		277,000
Year four	244,000		244,000		142,000
Year five	129,000		129,000		127,000
Prior	738,000		738,000		481,000
Revolving Loans	1,690,000		1,690,000		1,460,000
Revolving Loans Converted to Term Loans	41,000		41,000		31,000
Total	3,693,000		3,693,000		3,089,000
Commercial and industrial | Criticized nonaccrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	5,000		5,000		29,000
Year two	45,000		45,000		68,000
Year three	97,000		97,000		56,000
Year four	57,000		57,000		75,000
Year five	62,000		62,000		36,000
Prior	221,000		221,000		150,000
Revolving Loans	301,000		301,000		243,000
Revolving Loans Converted to Term Loans	17,000		17,000		13,000
Total	805,000		805,000		670,000
Commercial Real Estate
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total	43,000	$ 99,000	68,000	$ 128,000
Commercial Real Estate | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	339,000		339,000		2,275,000
Year two	2,041,000		2,041,000		2,679,000
Year three	2,125,000		2,125,000		1,835,000
Year four	1,655,000		1,655,000		2,580,000
Year five	2,592,000		2,592,000		4,118,000
Prior	13,611,000		13,611,000		11,340,000
Revolving Loans	403,000		403,000		450,000
Revolving Loans Converted to Term Loans	0		0		0
Total	22,766,000		22,766,000		25,277,000
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Year one	0		0
Year two	4,000		4,000
Year three	0		0
Year four	0		0
Year five	5,000		5,000
Prior	30,000		43,000
Revolving Loans	0		0
Revolving Loans Converted to Term Loans	0		0
Total	39,000		52,000
Commercial Real Estate | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	339,000		339,000		2,048,000
Year two	1,747,000		1,747,000		1,742,000
Year three	1,377,000		1,377,000		1,367,000
Year four	1,178,000		1,178,000		2,011,000
Year five	1,860,000		1,860,000		3,059,000
Prior	10,663,000		10,663,000		8,491,000
Revolving Loans	395,000		395,000		440,000
Revolving Loans Converted to Term Loans	0		0		0
Total	17,559,000		17,559,000		19,158,000
Commercial Real Estate | Commercial | Criticized accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	0		0		227,000
Year two	294,000		294,000		891,000
Year three	726,000		726,000		465,000
Year four	445,000		445,000		456,000
Year five	695,000		695,000		966,000
Prior	2,333,000		2,333,000		2,238,000
Revolving Loans	7,000		7,000		7,000
Revolving Loans Converted to Term Loans	0		0		0
Total	4,500,000		4,500,000		5,250,000
Commercial Real Estate | Commercial | Criticized nonaccrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	0		0		0
Year two	0		0		46,000
Year three	22,000		22,000		3,000
Year four	32,000		32,000		113,000
Year five	37,000		37,000		93,000
Prior	615,000		615,000		611,000
Revolving Loans	1,000		1,000		3,000
Revolving Loans Converted to Term Loans	0		0		0
Total	707,000		707,000		869,000
Commercial Real Estate | Residential builder and developer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	240,000		240,000		531,000
Year two	431,000		431,000		270,000
Year three	164,000		164,000		74,000
Year four	35,000		35,000		6,000
Year five	4,000		4,000		61,000
Prior	43,000		43,000		12,000
Revolving Loans	113,000		113,000		119,000
Revolving Loans Converted to Term Loans	0		0		0
Total	1,030,000		1,030,000		1,073,000
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Year one	0		0
Year two	0		0
Year three	0		0
Year four	0		0
Year five	0		0
Prior	1,000		2,000
Revolving Loans	0		0
Revolving Loans Converted to Term Loans	0		0
Total	1,000		2,000
Commercial Real Estate | Residential builder and developer | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	234,000		234,000		530,000
Year two	379,000		379,000		252,000
Year three	119,000		119,000		41,000
Year four	24,000		24,000		6,000
Year five	4,000		4,000		2,000
Prior	11,000		11,000		12,000
Revolving Loans	113,000		113,000		116,000
Revolving Loans Converted to Term Loans	0		0		0
Total	884,000		884,000		959,000
Commercial Real Estate | Residential builder and developer | Criticized accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	6,000		6,000		1,000
Year two	52,000		52,000		18,000
Year three	45,000		45,000		30,000
Year four	10,000		10,000		0
Year five	0		0		59,000
Prior	31,000		31,000		0
Revolving Loans	0		0		3,000
Revolving Loans Converted to Term Loans	0		0		0
Total	144,000		144,000		111,000
Commercial Real Estate | Residential builder and developer | Criticized nonaccrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	0		0		0
Year two	0		0		0
Year three	0		0		3,000
Year four	1,000		1,000		0
Year five	0		0		0
Prior	1,000		1,000		0
Revolving Loans	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	2,000		2,000		3,000
Commercial Real Estate | Other commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	43,000		43,000		866,000
Year two	1,272,000		1,272,000		1,771,000
Year three	1,878,000		1,878,000		1,051,000
Year four	975,000		975,000		1,110,000
Year five	645,000		645,000		1,261,000
Prior	871,000		871,000		562,000
Revolving Loans	52,000		52,000		32,000
Revolving Loans Converted to Term Loans	0		0		0
Total	5,736,000		5,736,000		6,653,000
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Year one	0		0
Year two	0		0
Year three	0		2,000
Year four	0		0
Year five	0		0
Prior	3,000		10,000
Revolving Loans	0		2,000
Revolving Loans Converted to Term Loans	0		0
Total	3,000		14,000
Commercial Real Estate | Other commercial construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	43,000		43,000		813,000
Year two	1,171,000		1,171,000		1,366,000
Year three	1,184,000		1,184,000		651,000
Year four	517,000		517,000		373,000
Year five	242,000		242,000		646,000
Prior	332,000		332,000		187,000
Revolving Loans	44,000		44,000		30,000
Revolving Loans Converted to Term Loans	0		0		0
Total	3,533,000		3,533,000		4,066,000
Commercial Real Estate | Other commercial construction | Criticized accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	0		0		53,000
Year two	101,000		101,000		391,000
Year three	693,000		693,000		390,000
Year four	449,000		449,000		691,000
Year five	358,000		358,000		565,000
Prior	517,000		517,000		326,000
Revolving Loans	8,000		8,000		0
Revolving Loans Converted to Term Loans	0		0		0
Total	2,126,000		2,126,000		2,416,000
Commercial Real Estate | Other commercial construction | Criticized nonaccrual
Financing Receivable, Credit Quality Indicator [Line Items]
Year one	0		0		0
Year two	0		0		14,000
Year three	1,000		1,000		10,000
Year four	9,000		9,000		46,000
Year five	45,000		45,000		50,000
Prior	22,000		22,000		49,000
Revolving Loans	0		0		2,000
Revolving Loans Converted to Term Loans	0		0		0
Total	$ 77,000		$ 77,000		$ 171,000