Supplemental Cash Flow Disclosures - Non-cash Investing and Financing Activities (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash paid during the year for:
Interest	$ 207,503,000	$ 220,151,000	$ 139,872,000
Income taxes	34,662,000	32,201,000	37,526,000
Non-cash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	6,565,000	5,726,000	4,229,000
Fair value of loans transferred from held to maturity to available for sale	319,075,000	106,090,000	152,613,000
Transfer of Loans Held-for-sale to Portfolio Loans	7,719,000	4,886,000	519,000
Gross (decrease) increase in market value adjustment to securities available for sale	38,086,000	(2,685,000)	18,602,000
Unsettled Treasury Stock Transactions	320,000	0	0
Gross increase in market value adjustment to derivatives	9,987,000	14,379,000	13,462,000
Increase in Commitment to Limited Partnership	0	0	302,000
Noncash or Part Noncash Acquisition, Value of Liabilities Assumed	27,035,000	0	66,477,000
Other Significant Noncash Transaction, Consideration Received	75,000	188,000	0
Treasury stock reissued	2,339,000	2,325,000	1,966,000
Sales and Excise Tax Payable	341,000	87,000	118,000
Contribution of Property	$ 0	$ 149,000	$ 0