Loans Receivable, Net - Loans Receivable Based On Our Internal Risk Ratings, Separated By Year Of Origination (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Held-to-maturity	$ 76,708	$ 75,722
Two Thousand And Eighteen Single Asset Securitization [Member]
Debt Securities, Held-to-maturity	$ 76,700	$ 75,700