FAIR VALUE DISCLOSURES AND REPORTING, THE FAIR VALUE OPTION AND FAIR VALUE MEASUREMENTS - Fair Values of Off-Balance Sheet Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Cash and cash equivalents	$ 356,771	$ 919,713
Securities available-for-sale:	1,489,247	1,751,832
Amortized Cost	593,154	0
Securities held-to-maturity	561,333	0
Loans, net	3,092,524	2,928,811
Accrued interest receivable	24,543	23,256
Liabilities:
Noninterest-bearing deposits	822,841	756,118
Interest-bearing deposits	4,483,356	4,470,666
Subordinated debentures	144,876	144,726
Accrued interest payable	1,607	1,711
U.S. Treasury
Assets:
Securities available-for-sale:	126,841	135,158
Obligations of U.S. Government agencies and sponsored entities
Assets:
Securities available-for-sale:	158,660	183,021
Municipal securities
Assets:
Securities available-for-sale:	591,818	708,502
Mortgage-backed securities
Assets:
Securities available-for-sale:	574,634	688,298
Corporate obligations
Assets:
Securities available-for-sale:	37,294	36,853
Quoted Prices (Level 1)
Assets:
Cash and cash equivalents	356,771	919,713
Securities held-to-maturity	0
Loans, net	0	0
Accrued interest receivable	0	0
Liabilities:
Noninterest-bearing deposits	0	0
Interest-bearing deposits	0	0
Subordinated debentures	0	0
Accrued interest payable	0	0
Quoted Prices (Level 1) \| U.S. Treasury
Assets:
Securities available-for-sale:	126,841	135,158
Quoted Prices (Level 1) \| Obligations of U.S. Government agencies and sponsored entities
Assets:
Securities available-for-sale:	0	0
Quoted Prices (Level 1) \| Municipal securities
Assets:
Securities available-for-sale:	0	0
Quoted Prices (Level 1) \| Mortgage-backed securities
Assets:
Securities available-for-sale:	0	0
Quoted Prices (Level 1) \| Corporate obligations
Assets:
Securities available-for-sale:	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Securities held-to-maturity	561,333
Loans, net	0	0
Accrued interest receivable	9,211	6,838
Liabilities:
Noninterest-bearing deposits	822,841	756,118
Interest-bearing deposits	4,331,370	4,431,771
Subordinated debentures	0	0
Accrued interest payable	1,607	1,711
Significant Other Observable Inputs (Level 2) \| U.S. Treasury
Assets:
Securities available-for-sale:	0	0
Significant Other Observable Inputs (Level 2) \| Obligations of U.S. Government agencies and sponsored entities
Assets:
Securities available-for-sale:	158,660	183,021
Significant Other Observable Inputs (Level 2) \| Municipal securities
Assets:
Securities available-for-sale:	573,561	688,379
Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities
Assets:
Securities available-for-sale:	574,634	688,298
Significant Other Observable Inputs (Level 2) \| Corporate obligations
Assets:
Securities available-for-sale:	37,262	36,810
Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Securities held-to-maturity	0
Loans, net	3,115,862	2,956,297
Accrued interest receivable	15,332	16,418
Liabilities:
Noninterest-bearing deposits	0	0
Interest-bearing deposits	0	0
Subordinated debentures	145,055	156,952
Accrued interest payable	0	0
Significant Unobservable Inputs (Level 3) \| U.S. Treasury
Assets:
Securities available-for-sale:	0	0
Significant Unobservable Inputs (Level 3) \| Obligations of U.S. Government agencies and sponsored entities
Assets:
Securities available-for-sale:	0	0
Significant Unobservable Inputs (Level 3) \| Municipal securities
Assets:
Securities available-for-sale:	18,257	20,123
Significant Unobservable Inputs (Level 3) \| Mortgage-backed securities
Assets:
Securities available-for-sale:	0	0
Significant Unobservable Inputs (Level 3) \| Corporate obligations
Assets:
Securities available-for-sale:	32	43
Estimated Fair Value
Assets:
Cash and cash equivalents	356,771	919,713
Securities held-to-maturity	561,333
Loans, net	3,115,862	2,956,297
Accrued interest receivable	24,543	23,256
Liabilities:
Noninterest-bearing deposits	822,841	756,118
Interest-bearing deposits	4,331,370	4,431,771
Subordinated debentures	145,055	156,952
Accrued interest payable	1,607	1,711
Estimated Fair Value \| U.S. Treasury
Assets:
Securities available-for-sale:	126,841	135,158
Estimated Fair Value \| Obligations of U.S. Government agencies and sponsored entities
Assets:
Securities available-for-sale:	158,660	183,021
Estimated Fair Value \| Municipal securities
Assets:
Securities available-for-sale:	591,818	708,502
Estimated Fair Value \| Mortgage-backed securities
Assets:
Securities available-for-sale:	574,634	688,298
Estimated Fair Value \| Corporate obligations
Assets:
Securities available-for-sale:	$ 37,294	$ 36,853

The sum of cash and cash equivalents plus Federal Funds Sold. Cash and cash equivalents consist of short term, highly liquid investments that are readily convertible to known amounts of cash and are so near their maturity that they present negligible risk of changes in value due to changes in interest rates -- usually with an original maturity less than 90 days.

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Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

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