BUSINESS	9 Months Ended
Sep. 30, 2014
BUSINESS [Abstract]
BUSINESS	NOTE 1 ¾ BUSINESS Capstead Mortgage Corporation operates as a self-managed real estate investment trust for federal income tax purposes (a “REIT”) and is based in Dallas, Texas. Unless the context otherwise indicates, Capstead Mortgage Corporation, together with its subsidiaries, is referred to as “Capstead” or the “Company.” Capstead earns income from investing in a leveraged portfolio of residential mortgage pass-through securities consisting almost exclusively of adjustable-rate mortgage (“ARM”) securities issued and guaranteed by government-sponsored enterprises, either Fannie Mae or Freddie Mac (together, the “GSEs”), or by an agency of the federal government, Ginnie Mae. Residential mortgage pass-through securities guaranteed by the GSEs or Ginnie Mae are referred to as “Agency Securities” and are considered to have limited, if any, credit risk.

BUSINESS

9 Months Ended

Sep. 30, 2014

NOTE 1 ¾ BUSINESS

Capstead Mortgage Corporation operates as a self-managed real estate investment trust for federal income tax purposes (a “REIT”) and is based in Dallas, Texas. Unless the context otherwise indicates, Capstead Mortgage Corporation, together with its subsidiaries, is referred to as “Capstead” or the “Company.” Capstead earns income from investing in a leveraged portfolio of residential mortgage pass-through securities consisting almost exclusively of adjustable-rate mortgage (“ARM”) securities issued and guaranteed by government-sponsored enterprises, either Fannie Mae or Freddie Mac (together, the “GSEs”), or by an agency of the federal government, Ginnie Mae. Residential mortgage pass-through securities guaranteed by the GSEs or Ginnie Mae are referred to as “Agency Securities” and are considered to have limited, if any, credit risk.