Fair Values of Assets and Liabilities - Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	$ (1,041,380)	$ (831,223)
Assets, Fair Value Disclosure	1,114,587	938,309
Balance, beginning of period	8,289	7,465
Total gains or losses included in earnings		0
Total gains or losses included in other comprehensive income	0	0
Purchases	8,511	824
Issuances	0	0
Sales	0	0
Settlements	(649)	0
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance, end of period	16,151	8,289
Other Investments	12,838	12,227
Loans Held-for-sale, Fair Value Disclosure	18,583	33,436
Other Assets, Fair Value Disclosure	41,786	60,981
Other Liabilities, Fair Value Disclosure	34,263	61,308
Financial and Nonfinancial Liabilities, Fair Value Disclosure	34,263	61,308
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	1,670	1,670
Total gains or losses included in earnings	0	0
Total gains or losses included in other comprehensive income	0	0
Purchases	0	0
Issuances	0	0
Sales	0	0
Settlements	(500)	0
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance, end of period	1,170	1,670
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	6,619	5,795
Total gains or losses included in earnings	0	0
Total gains or losses included in other comprehensive income	0	0
Purchases	8,511	824
Issuances	0	0
Sales	0	0
Settlements	149	0
Transfers from Level 3	0	0
Transfers into Level 3	0
Balance, end of period	14,981	6,619
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(32,949)	(24,385)
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(5,662)	(7,230)
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(362,290)	(191,180)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(629,974)	(496,033)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(981)	(100,998)
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(9,524)	(11,397)
Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Assets, Fair Value Disclosure	0	0
Other Investments	0
Loans Held-for-sale, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Other Liabilities, Fair Value Disclosure	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Level 1 [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(1,041,380)	(831,223)
Assets, Fair Value Disclosure	1,098,436	930,020
Other Investments	11,668	10,557
Loans Held-for-sale, Fair Value Disclosure	18,583	33,436
Other Assets, Fair Value Disclosure	26,805	54,362
Other Liabilities, Fair Value Disclosure	34,263	61,308
Financial and Nonfinancial Liabilities, Fair Value Disclosure	34,263	61,308
Fair Value, Inputs, Level 2 [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(32,949)	(24,385)
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(5,662)	(7,230)
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(362,290)	(191,180)
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(629,974)	(496,033)
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(981)	(100,998)
Fair Value, Inputs, Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(9,524)	(11,397)
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Assets, Fair Value Disclosure	16,151	8,289
Loans Held-for-sale, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	14,981	6,619
Other Liabilities, Fair Value Disclosure	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other Investments	1,170	1,670
Fair Value, Inputs, Level 3 [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	$ 0	$ 0