Note 2 - Organization and Nature of Business Operations (Detail) (USD $)	1 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2013	Dec. 31, 2012	Nov. 02, 2012	Sep. 24, 2012	Jun. 18, 2012
Proceeds from Contributed Capital (in Dollars)		$ 1,000
Stock Issued During Period, Shares, New Issues		50
Common Stock, Par or Stated Value Per Share (in Dollars per share)			$ 0.001	$ 0.001			$ 0.001
Common Stock, Shares Authorized (in Shares)			250,000,000	250,000,000		250,000,000	1,000
Preferred Stock, Shares Authorized (in Shares)			25,000,000	25,000,000		25,000,000
Preferred Stock, Par or Stated Value Per Share (in Dollars per share)			$ 0.001	$ 0.001		$ 0.001
(in Dollars per share)	$ 20.00
Proceeds from Issuance of Common Stock (in Dollars)	$ 150,000,000
Over-Allotment Option to Purchase Additional Common Stock					1,087,500
Percentage of Portfolio Invested in Agency Securities			88.70%	89.50%
Percentage of Portfolio Invested in Non-Agency Securities			11.30%	10.50%
IPO [Member]
Stock Issued During Period, Shares, New Issues	7,250,000
Private Placement [Member]
Stock Issued During Period, Shares, New Issues	250,000