FAIR VALUE MEASUREMENTS - Schedule of Fair Value of Derivative Instruments and Loans Held for Sale (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative notional amount and balance sheet location
Estimated Gain on Sale	$ 26,904	$ 62,863
Total Fair Value Adjustment	26,904	62,863
Derivative assets	10,357	61,824
Derivative Liabilities	(1,850)	(4,396)
Fair Value Adjustment To Loans Held for Sale	18,397	5,435
Loans Held for Sale
Derivative notional amount and balance sheet location
Notional or Principal Amount	933,432	1,852,923
Estimated Gain on Sale	19,317	47,019
Interest Rate Movement	(920)	(41,584)
Total Fair Value Adjustment	18,397	5,435
Fair Value Adjustment To Loans Held for Sale	18,397	5,435
Rate Lock Commitments
Derivative notional amount and balance sheet location
Notional or Principal Amount	241,760	395,462
Estimated Gain on Sale	7,587	15,844
Interest Rate Movement	(678)	(2,275)
Total Fair Value Adjustment	6,909	13,569
Derivative assets	6,909	14,482
Derivative Liabilities		(913)
Forward Sale Contracts
Derivative notional amount and balance sheet location
Notional or Principal Amount	1,175,192	2,248,385
Interest Rate Movement	1,598	43,859
Total Fair Value Adjustment	1,598	43,859
Derivative assets	3,448	47,342
Derivative Liabilities	$ (1,850)	$ (3,483)