Related Party Transactions (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Advisory fees from affiliate	$ 82,663	$ 79,205	$ 58,073
Receivable for advisory and service fees, from affiliates	14,077	16,245
Chimera and CreXus [Member]
Advisory fees from affiliate	64,500	62,800
Receivable for advisory and service fees, from affiliates	$ 14,100	$ 16,300