FAIR VALUE MEASUREMENTS - Schedule of Carrying Amounts and the Fair Values of the Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial assets:
Cash and cash equivalents	$ 118,756	$ 136,988	$ 113,354	$ 170,563
Restricted cash	9,861	5,306	13,854	5,427
Pledged securities	84,850	72,190	$ 67,719	$ 49,651
Loans held for sale	1,858,358	2,499,111
Loans held for investment, net	220,377	231,493
Derivative assets	61,824	11,678
Financial liabilities:
Derivative liabilities	4,396	1,333
Warehouse notes payable	1,990,183	2,649,470
Note payable	164,163	164,462
Carrying Amount
Financial assets:
Cash and cash equivalents	118,756	136,988
Restricted cash	9,861	5,306
Pledged securities	84,850	72,190
Loans held for sale	1,858,358	2,499,111
Loans held for investment, net	220,377	231,493
Derivative assets	61,824	11,678
Total financial assets	2,354,026	2,956,766
Financial liabilities:
Derivative liabilities	4,396	1,333
Warehouse notes payable	1,990,183	2,649,470
Note payable	164,163	164,462
Total financial liabilities	2,158,742	2,815,265
Fair Value
Financial assets:
Cash and cash equivalents	118,756	136,988
Restricted cash	9,861	5,306
Pledged securities	84,850	72,190
Loans held for sale	1,858,358	2,499,111
Loans held for investment, net	222,313	233,370
Derivative assets	61,824	11,678
Total financial assets	2,355,962	2,958,643
Financial liabilities:
Derivative liabilities	4,396	1,333
Warehouse notes payable	1,992,111	2,652,011
Note payable	167,327	168,431
Total financial liabilities	$ 2,163,834	$ 2,821,775