SUBSEQUENT EVENTS - Allegiance Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Assets:
Securities	$ 511,282		$ 425,046
Premises and equipment	55,594		58,417
Goodwill	80,950		80,950
Other assets	23,843		19,394
Total assets	4,271,831		4,486,001
Liabilities:
Noninterest-bearing deposits	1,780,473		1,784,981
Interest-bearing deposits	1,943,301		2,046,303
Total deposits	3,723,774		3,831,284
Other liabilities	32,884		28,450
Total liabilities	3,770,406		3,923,876
Total shareholders' equity	501,425	$ 526,679	562,125	$ 564,593	$ 556,227	$ 546,451
Total liabilities and shareholders' equity	4,271,831		$ 4,486,001
Allegiance | Merger Agreement
Assets:
Cash and cash equivalents	118,567
Securities	1,618,995
Loans held for investment	4,591,912
Allowance for credit losses for loans	(52,147)
Loans, net	4,539,765
Premises and equipment	57,837
Goodwill	223,642
Other assets	171,536
Total assets	6,730,342
Liabilities:
Noninterest-bearing deposits	2,465,839
Interest-bearing deposits	3,194,880
Total deposits	5,660,719
Borrowed funds	257,000
Subordinated debt	109,241
Other liabilities	47,080
Total liabilities	6,074,040
Total shareholders' equity	656,302
Total liabilities and shareholders' equity	$ 6,730,342