LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES (Loans Stated at Face Amount, Net of Unearned Income) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	$ 15,066,930		$ 14,449,142
Total Allowance for credit losses	(120,683)	$ (116,512)	(110,768)	$ (104,184)	$ (102,591)	$ (99,787)
Total loans held for investment, net	14,946,247		14,338,374
Loans receivable, deferred fees and costs	51,100		50,400
Construction and Land Development
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	1,231,720		1,101,260
Commercial Real Estate - Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	1,952,189		1,982,608
Commercial Real Estate - Non-Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	4,113,318		3,996,130
Multifamily Real Estate
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	788,895		802,923
Commercial and Industrial
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	3,373,148		2,983,349
Residential 1-4 Family - Commercial
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	518,317		538,063
Residential 1-4 Family - Mortgage
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	1,017,698		940,275
Residential 1-4 Family - Revolving
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	600,339		585,184
Auto
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	585,756		592,976
Consumer
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	134,709		152,545
Other Commercial
Loans and Leases Receivable Disclosure [Line Items]
LHFI, net of deferred fees and costs	$ 750,841		$ 773,829