NONINTEREST INCOME - Credit/debit card and ATM Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Credit/debit card and ATM income
Revenue from External Customer [Line Items]
Noninterest fee income	$ 13,115	$ 11,239	$ 38,307	$ 31,753
Bailment fees
Revenue from External Customer [Line Items]
Noninterest fee income	6,580	7,188	20,388	19,869
Interchange fees
Revenue from External Customer [Line Items]
Noninterest fee income	6,234	3,766	17,073	11,073
Other card and ATM fees
Revenue from External Customer [Line Items]
Noninterest fee income	$ 301	$ 285	$ 846	$ 811

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