REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	$ 20,482	$ 17,564	$ 38,484	$ 33,230
Loan servicing income	1,338	1,807	3,067	3,561
Securities gains/(losses), net	3,580	(259)	5,155	1,182
Unrealized gain on equity securities, net	112	71	370	43
Net gains on sale of loans held for sale	4,343	6,800	7,519	10,851
Valuation adjustment on servicing rights	(364)	(216)	(953)	(218)
Income on bank owned life insurance	888	700	1,787	1,314
Other noninterest income	1,682	1,167	3,349	2,387
Total noninterest income out-of-scope of Topic 606	11,579	10,070	20,294	19,120
TOTAL NONINTEREST INCOME	32,061	27,634	58,778	52,350
Service charges and fees on deposit accounts
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	3,186	2,794	6,163	5,412
Overdraft fees
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	2,876	2,518	5,619	4,726
Customer service and other service fees
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	84	88	166	166
Credit card fee income
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	4,270	3,114	7,619	5,381
Debit card income
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	4,213	3,558	7,856	6,466
Total service charges and fees
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	14,629	12,072	27,423	22,151
Trust fees
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	4,825	4,615	9,299	9,295
Brokerage and insurance commissions
Disaggregation of Revenue [Line Items]
Service charges and fees on deposit accounts	$ 1,028	$ 877	$ 1,762	$ 1,784