Loans Receivable, Net - Overall Statistics for Loans Receivable Portfolio (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Floating rate loans	$ 216.3	$ 147.9
Average floor rate	1.27%	1.80%
Percentage of loans subject to yield maintenance, or other prepayment restrictions	64.00%	64.00%
Percentage of loans open to repayment by borrower without penalty	36.00%	36.00%
USD LIBOR [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of loans receivable by type	84.00%	84.00%