FAIR VALUE (Carrying Amounts and Fair Values of Company's Financial Instruments) (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financial Assets
Other equity securities	$ 51,803	$ 73,389
Loans, net of allowance	6,649,100	6,518,148
Other assets	113,171	110,823
Financial Liabilities
Time Deposits	1,542,322	1,526,161
Securities sold under retail repurchase agreements and federal funds purchased	213,605	327,429
Advances from FHLB	513,777	848,611
Subordinated debentures	209,406	37,425
Estimated fair value [member]
Financial Assets
Other equity securities	51,803	73,389
Loans, net of allowance	6,628,054	6,376,307
Other assets	113,171	110,823
Financial Liabilities
Time Deposits	1,547,116	1,536,238
Securities sold under retail repurchase agreements and federal funds purchased	213,605	327,429
Advances from FHLB	520,729	850,186
Subordinated debentures	200,864	33,588
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets
Other equity securities	0	0
Loans, net of allowance	0	0
Other assets	0	0
Financial Liabilities
Time Deposits	0	0
Securities sold under retail repurchase agreements and federal funds purchased	0	0
Advances from FHLB	0	0
Subordinated debentures	0	0
Significant Other Observable Inputs (Level 2)
Financial Assets
Other equity securities	51,803	73,389
Loans, net of allowance	0	0
Other assets	113,171	110,823
Financial Liabilities
Time Deposits	1,547,116	1,536,238
Securities sold under retail repurchase agreements and federal funds purchased	213,605	327,429
Advances from FHLB	520,729	850,186
Subordinated debentures	0	0
Significant Unobservable Inputs (Level 3)
Financial Assets
Other equity securities	0	0
Loans, net of allowance	6,628,054	6,376,307
Other assets	0	0
Financial Liabilities
Time Deposits	0	0
Securities sold under retail repurchase agreements and federal funds purchased	0	0
Advances from FHLB	0	0
Subordinated debentures	$ 200,864	$ 33,588