FAIR VALUE MEASUREMENTS - Schedule of Carrying Amounts and the Fair Values of the Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Financial assets:
Cash and cash equivalents	$ 53,338	$ 118,756	$ 60,993	$ 136,988
Restricted cash	15,768	9,861	17,611	5,306
Pledged securities	92,401	84,850	$ 78,491	$ 72,190
Loans held for sale	1,608,025	1,858,358
Loans held for investment, net	167,540	220,377
Derivative assets	24,991	61,824
Financial liabilities:
Derivative liabilities	500	4,396
Warehouse notes payable	1,630,268	1,990,183
Note payable	164,011	164,163
Carrying Amount
Financial assets:
Cash and cash equivalents	53,338	118,756
Restricted cash	15,768	9,861
Pledged securities	92,401	84,850
Loans held for sale	1,608,025	1,858,358
Loans held for investment, net	167,540	220,377
Derivative assets	24,991	61,824
Total financial assets	1,962,063	2,354,026
Financial liabilities:
Derivative liabilities	500	4,396
Warehouse notes payable	1,630,268	1,990,183
Note payable	164,011	164,163
Total financial liabilities	1,794,779	2,158,742
Fair Value
Financial assets:
Cash and cash equivalents	53,338	118,756
Restricted cash	15,768	9,861
Pledged securities	92,401	84,850
Loans held for sale	1,608,025	1,858,358
Loans held for investment, net	168,662	222,313
Derivative assets	24,991	61,824
Total financial assets	1,963,185	2,355,962
Financial liabilities:
Derivative liabilities	500	4,396
Warehouse notes payable	1,630,890	1,992,111
Note payable	166,775	167,327
Total financial liabilities	$ 1,798,165	$ 2,163,834