FAIR VALUE MEASUREMENTS - General information (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Loans Held for Sale
Other information
Period of originated loans within which they are transferred or sold	60 days
Maximum | Pledged securities
Other information
Maximum term of maturity of investments	90 days
Maximum | Loans Held for Investment
Other information
Investment period for loans held for investment	3 years
Level 3 | Loans Held for Investment
Other information
Credit-related adjustments	$ 0.0	$ 0.0