INCOME TAXES - Schedule of Effective Income Tax Rate Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
INCOME TAXES [Abstract]
Income taxes computed at the federal statutory rate	$ 44,270	$ 57,269	$ 37,171
Benefit of REIT status	(44,270)	(57,268)	(37,183)
Income taxes computed on income of Capstead's sole taxable REIT subsidiary	0	1	(12)
Change in net deferred income tax assets	1	(1)	22
Other	(1)	0	(10)
Income tax provision	$ 0	$ 0	$ 0