Reverse Repurchase Agreements (Detail) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Reverse Repurchase Agreement:
Reverse repurchase agreement with non-affiliate - value	$ 593,865	$ 1,006,163	[1]
RCap [Member]
Reverse Repurchase Agreement:
Reverse repurchase agreement with non-affiliate - value	593,865	1,006,163
Shannon [Member]
Reverse Repurchase Agreement:
Reverse repurchase agreement with non-affiliate - value	$ 5,000

[1] Derived from the audited consolidated financial statements at December 31, 2010.