LOANS - Impaired Loans Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Impaired loans summary
Nonaccrual loans	$ 55,565	$ 47,892
Accruing loans past due 90 days or more	5,412	375
Restructured loans - nonaccrual	9,298	9,446
Restructured loans - accruing	13,623	13,093
Total nonperforming loans	83,898	70,806
Originated
Impaired loans summary
Nonaccrual loans	52,156	43,797
Accruing loans past due 90 days or more	3,680	375
Restructured loans - nonaccrual	8,023	8,063
Restructured loans - accruing	4,360	4,255
Total nonperforming loans	68,219	56,490
Acquired
Impaired loans summary
Nonaccrual loans	3,409	4,095
Accruing loans past due 90 days or more	1,732	0
Restructured loans - nonaccrual	1,275	1,383
Restructured loans - accruing	9,263	8,838
Total nonperforming loans	$ 15,679	$ 14,316