Related Party Transactions (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Advisory fees from affiliate	$ 20,460	$ 20,828	$ 20,710	$ 17,207	$ 16,321	$ 15,343	$ 13,863	$ 12,546	$ 79,205	$ 58,073	$ 48,952
Receivable for advisory and service fees, from affiliates	16,245				13,020				16,245	13,020
ChimeraAndCreXus [Member]
Advisory fees from affiliate									62,800	42,500
Receivable for advisory and service fees, from affiliates	$ 16,245				$ 13,020				$ 16,245	$ 13,020