DISCLOSURES ABOUT FAIR VALUE OF FINANCIAL INSTRUMENTS - Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Assets:
Cash and cash equivalents, Carrying Amount	$ 3,503,511	$ 3,785,931
Cash and cash equivalents, Estimated Fair Value	3,503,511	3,785,931
Debt securities, available for sale	1,846,566	1,985,438
Debt securities, held to maturity	853,126	991,937
Debt securities, held to maturity, fair value	794,435	934,677
Loans held for sale	32,963	204,794
Total loans and leases receivable, net of allowance for credit losses on loans and leases, Carrying Amount	15,232,019	14,311,987
Total loans and leases receivable, net of allowance for credit losses on loans and leases, Estimated Fair Value	14,954,795	14,104,884
FHLB, Federal Reserve Bank and other restricted stock, Carrying Amount	100,590	96,214
FHLB, Federal Reserve Bank and other restricted stock, Estimated Fair Value	100,590	96,214
Derivatives	13,611	15,263
Liabilities:
Deposits, Carrying Amount	18,976,018	18,846,461
Deposits, Estimated Fair Value	18,996,060	18,842,810
FHLB advances, Carrying Amount	1,195,377	1,128,352
FHLB advances, Estimated Fair Value	1,194,067	1,103,324
Other borrowings, Carrying Amount	99,138	99,068
Other borrowings, Estimated Fair Value	82,000	88,000
Subordinated debt, Carrying Amount	182,649	182,509
Subordinated debt, Estimated Fair Value	168,868	167,601
Derivative liabilities	18,824	22,570
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents, Estimated Fair Value	3,503,511	3,785,931
Debt securities, available for sale	0	0
Debt securities, held to maturity, fair value	0	0
Loans held for sale	0	0
Total loans and leases receivable, net of allowance for credit losses on loans and leases, Estimated Fair Value	0	0
FHLB, Federal Reserve Bank and other restricted stock, Estimated Fair Value	0	0
Derivatives	0	0
Liabilities:
Deposits, Estimated Fair Value	15,975,492	16,138,256
FHLB advances, Estimated Fair Value	0	0
Other borrowings, Estimated Fair Value	0	0
Subordinated debt, Estimated Fair Value	0	0
Derivative liabilities	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents, Estimated Fair Value	0	0
Debt securities, available for sale	1,617,868	1,972,202
Debt securities, held to maturity, fair value	443,000	461,307
Loans held for sale	5,180	1,836
Total loans and leases receivable, net of allowance for credit losses on loans and leases, Estimated Fair Value	1,536,254	1,321,128
FHLB, Federal Reserve Bank and other restricted stock, Estimated Fair Value	100,590	96,214
Derivatives	13,515	15,223
Liabilities:
Deposits, Estimated Fair Value	3,020,568	2,704,554
FHLB advances, Estimated Fair Value	1,194,067	1,103,324
Other borrowings, Estimated Fair Value	82,000	88,000
Subordinated debt, Estimated Fair Value	168,868	167,601
Derivative liabilities	18,824	22,570
Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents, Estimated Fair Value	0	0
Debt securities, available for sale	228,698	13,236
Debt securities, held to maturity, fair value	351,435	473,370
Loans held for sale	27,783	202,958
Total loans and leases receivable, net of allowance for credit losses on loans and leases, Estimated Fair Value	13,418,541	12,783,756
FHLB, Federal Reserve Bank and other restricted stock, Estimated Fair Value	0	0
Derivatives	96	40
Liabilities:
Deposits, Estimated Fair Value	0	0
FHLB advances, Estimated Fair Value	0	0
Other borrowings, Estimated Fair Value	0	0
Subordinated debt, Estimated Fair Value	0	0
Derivative liabilities	$ 0	$ 0