LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - PCI RECONCILIATION OF LOANS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Disclosures on loans acquired
Contractually receivable				$ 4,432,351	$ 4,147,249
Carrying value of loans				4,433,151	4,148,227
PCI loan
Disclosures on loans acquired
Contractually receivable				3,420	4,251
Non-accretable amount				(1,303)	(1,521)
Accretable amount	$ (31)	$ (50)	$ (140)	(31)	(50)
Carrying value of loans				$ 2,086	$ 2,680
Rollforward of the accretable discount on PCI loans
Balance at the beginning of the period	(50)	(140)	(3,600)
Transfers between non-accretable and accretable	(279)	(573)	(28)
Net accretion into interest income on loans, including loan fees	298	663	3,488
Balance at the end of the period	$ (31)	$ (50)	$ (140)