FAIR VALUE - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	$ 5,047,179	$ 5,229,984
Residential Mortgage Backed Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	2,527,054	2,633,161
MBS [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	2,676,144	2,784,779
Fair Value, Measurements, Recurring [Member]
Assets Fair Value Disclosure [Abstract]
Equity securities	4,871	4,893
Derivative Assets	239	341
Derivative Liabilities [Abstract]
Derivative Liabilities	242	317
Fair Value, Measurements, Recurring [Member] | U S Treasury Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	116,068	135,393
Fair Value, Measurements, Recurring [Member] | Government Agencies Debt Securities [Member] | Noncallable [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	467,940	433,437
Fair Value, Measurements, Recurring [Member] | Government Agencies Debt Securities [Member] | Call Option [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	1,785,476	1,874,960
Fair Value, Measurements, Recurring [Member] | MBS [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	2,676,144	2,784,779
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	1,551	1,415
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 1 [Member]
Assets Fair Value Disclosure [Abstract]
Equity securities	4,871	4,893
Derivative Assets	0	0
Derivative Liabilities [Abstract]
Derivative Liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 1 [Member] | U S Treasury Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	116,068	135,393
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 1 [Member] | Government Agencies Debt Securities [Member] | Noncallable [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 1 [Member] | Government Agencies Debt Securities [Member] | Call Option [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 1 [Member] | MBS [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 2 [Member]
Assets Fair Value Disclosure [Abstract]
Equity securities	0	0
Derivative Assets	239	341
Derivative Liabilities [Abstract]
Derivative Liabilities	242	317
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 2 [Member] | U S Treasury Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 2 [Member] | Government Agencies Debt Securities [Member] | Noncallable [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	467,940	433,437
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 2 [Member] | Government Agencies Debt Securities [Member] | Call Option [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	1,785,476	1,874,960
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 2 [Member] | MBS [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	2,671,420	2,779,994
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 3 [Member]
Assets Fair Value Disclosure [Abstract]
Equity securities	0	0
Derivative Assets	0	0
Derivative Liabilities [Abstract]
Derivative Liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 3 [Member] | U S Treasury Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 3 [Member] | Government Agencies Debt Securities [Member] | Noncallable [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 3 [Member] | Government Agencies Debt Securities [Member] | Call Option [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 3 [Member] | MBS [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	4,724	4,785
Fair Value, Measurements, Recurring [Member] | Fair Value Inputs Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure [Abstract]
Available-For-Sale Securities, Debt Securities	$ 1,551	$ 1,415