BASIS OF PRESENTATION, NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES - Cash flow reporting (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
BASIS OF PRESENTATION, NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES.
Cash collateral used in interest rate swap transactions	$ 1,800,000	$ 8,400,000
Supplemental disclosures of cash flow information:
Cash paid for taxes	6,659,000	11,307,000	$ 13,710,000
Cash paid for interest	6,122,000	10,679,000	17,040,000
Supplemental disclosures of non-cash flow information:
Operating lease right-to-use asset obtained in exchange for lease		1,700,000
Operating lease right-to-use asset increased (decreased) exchange for lease liabilities	(617,000)	1,876,000	14,499,000
Change in liability for dividends accrued	$ (824,000)	$ 22,000	1,306,000
Repossessed real estate and other assets			$ 121,000