LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES (Loans Stated at Face Amount, Net of Unearned Income) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	$ 15,283,620		$ 14,449,142
Total Allowance for credit losses	(125,627)	$ (120,683)	(110,768)	$ (108,009)	$ (104,184)	$ (99,787)
Total loans held for investment, net	15,157,993		14,338,374
Loans receivable, deferred fees and costs	58,400		50,400
Construction and Land Development
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	1,132,940		1,101,260
Commercial Real Estate - Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	1,975,281		1,982,608
Commercial Real Estate - Non-Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	4,148,218		3,996,130
Multifamily Real Estate
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	947,153		802,923
Commercial and Industrial
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	3,432,319		2,983,349
Residential 1-4 Family - Commercial
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	517,034		538,063
Residential 1-4 Family - Mortgage
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	1,057,294		940,275
Residential 1-4 Family - Revolving
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	599,282		585,184
Auto
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	534,361		592,976
Consumer
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	126,151		152,545
Other Commercial
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	$ 813,587		$ 773,829