Recent Developments, Including Mergers and Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	May 20, 2025	Dec. 31, 2024	Jun. 30, 2024
Business Combination Separately Recognized Transactions [Line Items]
Assets	$ 14,045,780		$ 13,554,314	$ 12,737,318
Loans held for investment (net of unearned interest)	8,114,488		8,025,110	8,047,448
Deposits	$ 12,056,192		$ 11,718,546	$ 11,015,602
American Bank of Oklahoma [Member]
Business Combination Separately Recognized Transactions [Line Items]
Assets		$ 385,000
Loans held for investment (net of unearned interest)		280,000
Deposits		$ 320,000