Condensed Financial Information - Parent Company Only - Condensed Statements of Cash Flows (Detail) - USD ($)		12 Months Ended
	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows from Operating Activities
Net Income		$ 107,369,000	$ 95,041,000	$ 57,518,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Gain on sale of equity securities		0	(9,000)	(1,213,000)
Benefit for credit losses		8,514,000	(10,896,000)	27,222,000
Long-term debt extinguishment costs	$ 831,000	0	831,000	0
Change in fair value of equity securities		1,302,000	285,000	552,000
Excess tax benefits (deficiencies)		69,000	(89,000)	(132,000)
Increase in other assets		(68,863,000)	36,589,000	(53,982,000)
Increase in other liabilities		41,813,000	(37,389,000)	50,434,000
Net Cash Provided by Operating Activities		124,696,000	95,103,000	84,991,000
Cash Flows from Investing Activities
Net cash used in acquisition		67,000	0	0
Purchase of equity securities		(1,217,000)	(2,959,000)	(2,772,000)
Proceeds from repayments and maturities of held to maturity securities		137,241,000	66,709,000	38,941,000
Proceeds from sales of equity securities		0	0	4,148,000
Net cash received from business acquisition		326,236,000	0	0
Net Cash Used in Investing Activities:		(651,861,000)	(615,290,000)	(928,022,000)
Cash Flows from Financing Activities
Cash dividends paid on common stock		(37,334,000)	(27,119,000)	(25,457,000)
Proceeds from issuance of subordinated debt, net		0	147,738,000	0
Redemption of subordinated debentures, net		0	(88,330,000)	0
Purchase of treasury stock		0	0	(1,452,000)
Retirement of restricted stock		(1,956,000)	(651,000)	(501,000)
Exercise of stock options		0	19,000	0
Net Cash Provided by Financing Activities:		534,585,000	478,627,000	830,750,000
Net increase (decrease) in cash and cash equivalents		7,420,000	(41,560,000)	(12,281,000)
Cash and cash equivalents, beginning of year		228,530,000	270,090,000	282,371,000
Cash and cash equivalents, end of year		235,950,000	228,530,000	270,090,000
Parent Company
Cash Flows from Operating Activities
Net Income		107,369,000	95,041,000	57,518,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Gain on sale of equity securities		0	0	(149,000)
Amortization of subordinated debt costs		487,000	547,000	37,000
Benefit for credit losses		0	0	(12,000)
Long-term debt extinguishment costs		0	831,000	0
Change in fair value of equity securities		0	0	786,000
Excess tax benefits (deficiencies)		69,000	(89,000)	(132,000)
Increase in other assets		(1,571,000)	(1,443,000)	(1,462,000)
Increase in other liabilities		142,000	149,000	25,000
Equity in undistributed income of subsidiaries		(60,139,000)	(49,831,000)	(32,915,000)
Net Cash Provided by Operating Activities		46,357,000	45,205,000	23,696,000
Cash Flows from Investing Activities
Purchase of equity securities		0	0	(49,000)
Proceeds from repayments and maturities of held to maturity securities		0	0	1,000,000
Proceeds from sales of equity securities		0	0	1,148,000
Contribution to subsidiary		0	(65,000,000)	0
Net Cash Used in Investing Activities:		67,000	(65,000,000)	2,099,000
Cash Flows from Financing Activities
Cash dividends paid on common stock		(37,334,000)	(27,119,000)	(25,457,000)
Proceeds from issuance of subordinated debt, net		0	147,738,000	0
Redemption of subordinated debentures, net		0	(88,330,000)	0
Purchase of treasury stock		0	0	(1,452,000)
Retirement of restricted stock		(1,956,000)	(651,000)	(501,000)
Exercise of stock options		0	19,000	0
Net Cash Provided by Financing Activities:		(39,290,000)	31,657,000	(27,410,000)
Net increase (decrease) in cash and cash equivalents		7,134,000	11,862,000	(1,615,000)
Cash and cash equivalents, beginning of year		40,228,000	28,366,000	29,981,000
Cash and cash equivalents, end of year		$ 47,362,000	$ 40,228,000	$ 28,366,000