NONINTEREST INCOME - Credit/debit card and ATM Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Credit/debit card and ATM income
Revenue from External Customer [Line Items]
Noninterest fee income	$ 13,677	$ 10,709	$ 25,192	$ 20,514
Bailment fees
Revenue from External Customer [Line Items]
Noninterest fee income	6,908	6,588	13,807	12,681
Interchange fees
Revenue from External Customer [Line Items]
Noninterest fee income	6,452	3,847	10,839	7,307
Other card and ATM fees
Revenue from External Customer [Line Items]
Noninterest fee income	$ 317	$ 274	$ 546	$ 526

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Name:	us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration