SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Contracts with Customers (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Contracts with Customers
Revenue from contracts with customer	$ 127,484	$ 95,714	$ 82,387
Contract assets with customers	0	0
Contract liabilities with customers	0	0
Loan Origination Fees \| Gains from Mortgage Banking Activities
Contracts with Customers
Revenue from contracts with customer	75,599	59,877	53,116
Investment Sales Broker Fees, Investment Management Fees, Assumption Fees, Application Fees and Other \| Other Revenues
Contracts with Customers
Revenue from contracts with customer	$ 51,885	$ 35,837	$ 29,271

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130531-203044

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130533-203044

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant