Loans Receivable - Overall Statistics for Loans Receivable Portfolio (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commitments expiration period	5 years
Percentage of loans subject to yield maintenance, lock-out provisions, or other prepayment restrictions	88.00%
Percentage of loans open to repayment by borrower	12.00%
One-Month USD LIBOR [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of loans receivable by type	83.00%
Three-Month GBP LIBOR [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of loans receivable by type	13.00%
Floating Rate Indices [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of loans receivable by type	4.00%
LIBOR [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of loans receivable by type	17.00%
Average floor rate	0.30%